RESUMO
During the ovarian ontogeny in birds, five fundamental events can be recognized: migration and colonization of the primordial germ cells, differentiation and proliferation of oogonies, an organization of germinal nests, beginning of the meiotic process and folliculogenesis. The knowledge of these events is fundamental for the interpretation of the processes involved in the differentiation of female gametes. However, there are only references for some model species such as Gallus gallus domesticus and Coturnix coturnix. In a previous study, the histological structure of embryonic ovaries of Columba livia was revealed. Therefore, the objective of this work is to characterize the processes of meiosis and folliculogenesis C. livia from the analysis of the expression of the GnRH receptor, the 3ßHSD enzyme and the cell proliferation protein PCNA in embryonic and postnatal ovaries. Therefore, the expression of GnRHR, 3ßHSD, and PCNA was revealed in histological testicular and ovarian preparations in embryos (stages 41-43) and neonates (2, 5, 7, 10 and 75â¯days post-hatching). The present study demonstrates that the fate of germline cells is dictated by their location during gonadal development. Thus, the germline cells located in the cortex of the left gonad enter meiosis, while those in the right gonad and those in the medulla of the left ovary fail to go into meiosis. This indicates that somatic signals, instead of an autonomous cellular mechanism, regulate the entry of the germline cells into meiosis in the C. livia embryo. Future studies will be focused on the analysis of proteins associated with meiotic events and folliculogenesis in embryonic and neonatal ovaries of C. livia, to evaluate the regulation of meiosis in vitro.
Assuntos
3-Hidroxiesteroide Desidrogenases/metabolismo , Columbidae/metabolismo , Meiose , Folículo Ovariano/crescimento & desenvolvimento , Receptores LHRH/metabolismo , Animais , Proliferação de Células , Columbidae/embriologia , Embrião não Mamífero/citologia , Feminino , Células Germinativas/metabolismo , Imuno-Histoquímica , Oócitos/citologia , Oócitos/metabolismo , Folículo Ovariano/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismoRESUMO
Analysis of rumen contents is helpful in solving poisoning cases when ingestion of a toxic substance by cattle or other ruminant animals is suspected. The most common technique employs extraction of the sample with organic solvent followed by clean-up method(s) before analysis with gas chromatography-mass spectrometry equipped with a library of mass spectra to help identify unknowns. A rapid method using magnesium sulfate, primary secondary amine, and C18 sorbents following principles of QuEChERS to clean up rumen contents samples is reported herein. The method was validated to analyze fortified bovine rumen contents to detect commonly found organophosphorus pesticides, carbamates, and several other compounds such as atropine, 4-aminopyridine, caffeine, scopolamine, 3-chloro-4-methylaniline, strychnine, metaldehyde, and metronidazole. For each compound, the ratio of 2 ions from the mass spectrum was monitored in fortified rumen contents. The ion ratio of fortified sample was compared with the ion ratio of standard sample spectrum and was found to be within 20%, with the exception of aldicarb and 4-aminopyridine with ion ratio of 26% and 29%, respectively. Usefulness of the method was demonstrated by not only analyzing bovine rumen contents but also canine and avian gastrointestinal contents submitted for organic chemical screening.
Assuntos
Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas/veterinária , Rúmen/química , Animais , Bovinos/metabolismo , Columbidae/metabolismo , Cães/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodosRESUMO
A via intranasal é uma boa alternativa por ser indolor e de fácil aplicação em aves. O objetivo deste estudo foi avaliar os efeitos anestésicos da associação de cetamina S+ e midazolam pela via intranasal (IN) em comparação com a via intramuscular (IM) em pombos. Foram utilizados 12 pombos alocados em dois grupos com 15 dias de intervalo, os quais receberam: grupo IM: 20 mg/kg de cetamina S+ associada a 3,5 mg/kg de midazolam pela via intramuscular (musculatura do peito); e grupo IN, mesmo protocolo, porém, pela via intranasal. Os parâmetros avaliados foram: período de latência, tempo de duração em decúbito dorsal, tempo total de anestesia, tempo de recuperação e efeitos adversos. Para a análise estatística, empregou-se o teste de Wilcoxon, com as diferenças consideradas significativas quando P<0,05. O período de latência obtido foi de 30 [30-47,5] e 40 [30-50] segundos para IM e IN, respectivamente. O tempo de duração de decúbito dorsal foi de 59 [53,25-65] e 63 [37-71,25] minutos para IM e IN, respectivamente, sem diferenças significativas entre os grupos. Com relação à duração total de anestesia, foi observada diferença significativa, com 88 [86,25-94,5] e 68 [53,5-93] minutos para os grupos IM e IN, respectivamente. O tempo de recuperação foi mais curto no grupo IN (15 [4,25-19,5]) comparado ao IM (32 [28,25-38,25] minutos). Dois animais de cada grupo apresentaram regurgitação na fase de recuperação. Conclui-se que a administração de cetamina S+ e midazolam pela via intranasal é um método aceitável de administração de fármacos e produz anestesia rápida e eficaz em pombos.
The intranasal route is a good alternative because is painless and easy to perform in birds. The objective of this study was to evaluate the anesthetic effects of S+ ketamine and midazolam administered by intranasal or intramuscular route in pigeons. Twelve animals were used in a randomized and crossover design. Animals received two treatments with 2-weeks interval. IM group: animals received 20mg/kg of S+ ketamine and 3.5mg/kg of midazolam by intramuscular route (pectoral muscles); IN group: animals received the same protocol by intranasal route. Parameters evaluated were: onset of action, time of duration in dorsal recumbency; total time of anesthesia and side effects. Statistical analysis was performed using Wilcoxon test and the differences were considered significant when P<0.05. Onset of action was 30 [30-47.5] and 40 [30-50] seconds for IM and IN respectively. Time of duration in dorsal recumbency was 59 [53.25-65] and 63 [37-71.25] minutes for IM and IN respectively, without significant differences between treatments. Total time of anesthesia was 88 [86.25-94.5] and 68 [53.5-93] minutes for IM and IN, respectively, with significant difference between groups. The recovery time was lower for IN (15[4.25-19.5] minutes) compared with IM (32 [28.25-38.25] minutes). Two animals of each group presented regurgitation in the recovery period. It was concluded that S+ ketamine and midazolam administered intranasal is an acceptable method of drug delivery and can be used to promote anesthesia in pigeons.
Assuntos
Animais , Administração Intranasal/veterinária , Columbidae/metabolismo , Injeções Intramusculares/veterinária , Ketamina/administração & dosagem , Midazolam/administração & dosagem , Período de Recuperação da Anestesia , Anestesia/efeitos adversosRESUMO
A via intranasal é uma boa alternativa por ser indolor e de fácil aplicação em aves. O objetivo deste estudo foi avaliar os efeitos anestésicos da associação de cetamina S+ e midazolam pela via intranasal (IN) em comparação com a via intramuscular (IM) em pombos. Foram utilizados 12 pombos alocados em dois grupos com 15 dias de intervalo, os quais receberam: grupo IM: 20 mg/kg de cetamina S+ associada a 3,5 mg/kg de midazolam pela via intramuscular (musculatura do peito); e grupo IN, mesmo protocolo, porém, pela via intranasal. Os parâmetros avaliados foram: período de latência, tempo de duração em decúbito dorsal, tempo total de anestesia, tempo de recuperação e efeitos adversos. Para a análise estatística, empregou-se o teste de Wilcoxon, com as diferenças consideradas significativas quando P<0,05. O período de latência obtido foi de 30 [30-47,5] e 40 [30-50] segundos para IM e IN, respectivamente. O tempo de duração de decúbito dorsal foi de 59 [53,25-65] e 63 [37-71,25] minutos para IM e IN, respectivamente, sem diferenças significativas entre os grupos. Com relação à duração total de anestesia, foi observada diferença significativa, com 88 [86,25-94,5] e 68 [53,5-93] minutos para os grupos IM e IN, respectivamente. O tempo de recuperação foi mais curto no grupo IN (15 [4,25-19,5]) comparado ao IM (32 [28,25-38,25] minutos). Dois animais de cada grupo apresentaram regurgitação na fase de recuperação. Conclui-se que a administração de cetamina S+ e midazolam pela via intranasal é um método aceitável de administração de fármacos e produz anestesia rápida e eficaz em pombos.(AU)
The intranasal route is a good alternative because is painless and easy to perform in birds. The objective of this study was to evaluate the anesthetic effects of S+ ketamine and midazolam administered by intranasal or intramuscular route in pigeons. Twelve animals were used in a randomized and crossover design. Animals received two treatments with 2-weeks interval. IM group: animals received 20mg/kg of S+ ketamine and 3.5mg/kg of midazolam by intramuscular route (pectoral muscles); IN group: animals received the same protocol by intranasal route. Parameters evaluated were: onset of action, time of duration in dorsal recumbency; total time of anesthesia and side effects. Statistical analysis was performed using Wilcoxon test and the differences were considered significant when P<0.05. Onset of action was 30 [30-47.5] and 40 [30-50] seconds for IM and IN respectively. Time of duration in dorsal recumbency was 59 [53.25-65] and 63 [37-71.25] minutes for IM and IN respectively, without significant differences between treatments. Total time of anesthesia was 88 [86.25-94.5] and 68 [53.5-93] minutes for IM and IN, respectively, with significant difference between groups. The recovery time was lower for IN (15[4.25-19.5] minutes) compared with IM (32 [28.25-38.25] minutes). Two animals of each group presented regurgitation in the recovery period. It was concluded that S+ ketamine and midazolam administered intranasal is an acceptable method of drug delivery and can be used to promote anesthesia in pigeons.(AU)
Assuntos
Animais , Columbidae/metabolismo , Administração Intranasal/veterinária , Ketamina/administração & dosagem , Midazolam/administração & dosagem , Injeções Intramusculares/veterinária , Anestesia/efeitos adversos , Período de Recuperação da AnestesiaRESUMO
Doublecortin (DCX) is a microtubule-associated protein essential for the migration of immature neurons in the developing and adult vertebrate brain. Herein, the distribution of DCX-immunoreactive (DCX-ir) cells in the prosencephalon of the adult pigeon (Columba livia) is described, in order to collect the evidence of their immature neural phenotype and to investigate their putative place of origin. Bipolar and multipolar DCX-ir cells were observed to be widespread throughout the parenchyma of the adult pigeon forebrain. Small, bipolar and fusiform DCX-ir cells were especially concentrated at the tips of the lateral walls of the lateral ventricles (VZ) and sparsely distributed in the remaining ependyma. Multipolar DCX-ir cells populated the pallial regions. None of these DCX-ir cells seemed to co-express NeuN or GFAP, suggesting that they were immature neurons. Two different migratory-like routes of DCX-ir cells from the VZ toward different targets in the parenchyma were putatively identified: (i) rostral migratory-like bundle; and (ii) lateral migratory-like bundle. In addition, pial surface bundles and intra-ependymal fascicles were also observed. Pigeons treated with 5-bromo-desoxyuridine (BrdU, 3 intraperitoneal injections of 100mg/kg 2h apart, sacrificed 2h after last injection) displayed BrdU-immunoreactive cells (BrdU-ir) in VZ and ependyma whereas the parenchyma was free of such cells. Despite the regional overlapping, there was no evidence of double-labeling between BrdU and DCX. Therefore, the VZ in the brain of adult pigeons seems to have rapidly dividing cells as putative progenitors of newborn neurons populating the forebrain. The distribution of the newborn neurons in the avian prosencephalon and their migration pathways appear to be larger than in mammals, suggesting that the morphological turnover of forebrain circuits is an important mechanism for brain plasticity in avian species during adulthood.
Assuntos
Encéfalo/metabolismo , Columbidae/metabolismo , Proteínas Associadas aos Microtúbulos/biossíntese , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neuropeptídeos/biossíntese , Animais , Encéfalo/citologia , Diferenciação Celular/fisiologia , Movimento Celular/fisiologia , Columbidae/anatomia & histologia , Proteínas do Domínio Duplacortina , Feminino , Imuno-Histoquímica , Masculino , Proteínas Associadas aos Microtúbulos/análise , Neurogênese/fisiologia , Neuropeptídeos/análiseRESUMO
This study quantifies metal concentrations in washed and unwashed feathers of feral pigeons (Columba livia). The material was collected in two different sites: Goiânia (capital of Goiás State), with high anthropic activities, and Jataí (a city in Goiás), with low anthropic activities. Results revealed that metals such as Pb, Cr, and Cd were deposited in the feathers originating from air and soil (exogenous process). Other metals such as Cu, Fe, Mn, and Zn, which are part of the tissue constitution of a living being, were absorbed through the pigeons' diet (endogenous process). There was a statistically significant difference between mean values of Cd, Pb, and Cr in the three collection sites. The order of metal concentrations were Civic Square > Zoo > Jataí, which shows highest levels of metal contamination in anthropic environments. Significant differences between Cd, Pb, and Cr in washed and unwashed feathers suggest that metal concentrations are directly related to exposure time due to exogenous sources. We concluded that it is possible to quantify and monitor metal levels in the environment by analyzing the feathers of urban feral pigeons. Furthermore, unwashed feathers were especially efficient to investigate endogenous and exogenous absorption of the metals in our study.
Assuntos
Columbidae/metabolismo , Monitoramento Ambiental/métodos , Poluentes Ambientais/metabolismo , Plumas/metabolismo , Metais/metabolismo , Animais , Brasil , Poluentes Ambientais/análise , Poluição Ambiental/estatística & dados numéricos , Plumas/química , Metais/análise , Espectrofotometria AtômicaRESUMO
The compositions of the glutamate AMPA-type receptors influence the neural response and the subunits GluR2/3 has been referred to as essential for receptor trafficking and synapse consolidation. We investigate the GluR2/3 occurrence and expression in the hippocampal formation of newly born homing pigeons by a semi-quantitative approach, the Western-blotting technique and by immunohistochemistry. Immunoreactivity for GluR2/3 occurs before hatching has been evident in neuropil that was fully dispersed over the hippocampus proper (HP) and the area parahippocampalis (APH). Although many HP cells are NeuN-positives, a specific neuronal protein indicating that they are already differentiated as neurons while not one contains GluR2/3 at the hatching day (P0). Few neurons at the APH seem to express GluR2/3 at P0, but 3 days later (P3) the GluR2/3 labeling can be recognized in many HP neurons, showing a distribution pattern that resembles the adult, gradually increasing in intensity until P10. Also, the Western-blot shows an augment between P0 and P3, remaining stable after that. The enhancement of the neuronal label at P3 coincides with the retraction of the GluR2/3 label in neuropil, reducing their occurrence during the maturational period to become restricted to the dorsomedial portion as reported for adults. As the HP GluR2/3-containing cells are supposedly projecting neurons, taking together, the results signalize the relevance of the GluR2/3 in post-hatch formation of avian hippocampal circuitry in which the third day seems to be the critical period.
Assuntos
Columbidae/metabolismo , Hipocampo/metabolismo , Subunidades Proteicas/metabolismo , Receptores de AMPA/metabolismo , Fatores Etários , Animais , Western Blotting , Imuno-Histoquímica , Neurônios/metabolismoRESUMO
The distribution of tryptophan hydroxylase (TPH)-containing perikarya and processes in the brainstem and diencephalon of the pigeon (Columba livia) were investigated using single-labeling chromogenic and double-labeling fluorescence immunohistochemical methods for TPH and 5-HT. TPH-immunoreactive (TPH-ir) perikarya were seen extending from the caudal medulla to mid-hypothalamic levels, located in brainstem regions previously described as containing 5-HT-ir somata. Brainstem TPH-ir cell clusters (the midline raphe, and the dorsolateral and ventrolateral serotonergic cell groups) and the circumventricular cerebrospinal fluid-contacting neurons in the taenia choroidea (in the caudal brainstem), recessus infundibuli and paraventricular organ (in the hypothalamus) were shown to co-express 5-HT immunoreactivity. However, heavily labeled TPH-ir cell clusters were observed in the nucleus premamillaris (PMM), in the stratum cellulare internum (SCI), in the nucleus paraventricularis magnocellularis (PVN) and in the medial border of the nucleus dorsomedialis anterior thalami (DMA). Double-labeling experiments indicated that none of these medial hypothalamic TPH-ir cells were immunoreactive to 5-HT. These cells correspond to dopamine- and melatonin-containing neurons previously found in the avian hypothalamus, and appear to be comparable to the mammalian TPH-ir hypothalamic A11-A13 catecholaminergic somata, suggesting that they may be a conserved attribute in the amniote medial hypothalamus.
Assuntos
Tronco Encefálico/enzimologia , Columbidae/metabolismo , Diencéfalo/enzimologia , Neurônios/enzimologia , Serotonina/biossíntese , Triptofano Hidroxilase/metabolismo , Animais , Evolução Biológica , Mapeamento Encefálico , Tronco Encefálico/anatomia & histologia , Columbidae/anatomia & histologia , Diencéfalo/anatomia & histologia , Dopamina/metabolismo , Feminino , Hipotálamo/citologia , Hipotálamo/enzimologia , Imuno-Histoquímica , Masculino , Melatonina/metabolismo , Núcleos da Rafe/citologia , Núcleos da Rafe/enzimologia , Especificidade da Espécie , Transmissão Sináptica/fisiologia , Terceiro Ventrículo/citologia , Terceiro Ventrículo/enzimologiaRESUMO
In the present study, the acute behavioral and ingestive effects of ICV injections of mammalian orexin-A (ORXA; vehicle, 0.2, 0.6 or 2 nmol) and of orexin-B (ORXB; vehicle, 0.2, 0.6 or 2 nmol), as well as possible long-term effects (through 24 h of continuous intake monitoring after 0.6 nmol of ORXA or ORXB) of these treatments in food/water intake and in blood levels of metabolic fuels (free fatty acids and glucose, after 0.2 or 0.6 nmol of ORXA) were examined in adult male pigeons. Both ORXA and ORXB treatments failed to produce acute (1-3 h) or long-term effects on feeding and drinking behaviors, and did not change blood free fatty acids and glucose 15 and 30 min after treatments, as compared to vehicle-treated animals. However, ORXA (but not ORXB) treatments evoked a dose-related, intense increase in exploratory behaviors, associated to reduced time spent in alert immobility and sleep-typical postures. These data substantiate the lack of orexigenic effects of ORXs in avian species, and suggest that an important role in vigilance control may represent a conserved functional attribute of orexinergic circuits in vertebrates.
Assuntos
Comportamento Animal/efeitos dos fármacos , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/farmacologia , Neuropeptídeos/farmacologia , Animais , Columbidae/metabolismo , Relação Dose-Resposta a Droga , Injeções Intraventriculares , Peptídeos e Proteínas de Sinalização Intracelular/administração & dosagem , Masculino , Neuropeptídeos/administração & dosagem , Orexinas , Sono/efeitos dos fármacosRESUMO
The Pin-tailed Manakin (Ilicura militaris) is a small, sexually dimorphic, frugivorous suboscine songbird (Pipridae; Passeriformes; Aves) endemic to the Atlantic Forest of Brazil. A variant individual of this species was recently described in which the red patches that characterise the male's Definitive plumage were replaced by orange-yellow ones. We show here that the pigments in the feathers of the colour variant are common dietary carotenoids (zeaxanthin, beta-cryptoxanthin), not carotenoids synthesised by birds, lending support to the suggestion that the individual is a colour mutant lacking the capability to transform yellow dietary pigments into the red pigments normally present in these feathers. By comparison, the yellow crown feathers of a close relative, the Golden-winged Manakin (Masius chrysopterus), contained predominantly endogenously produced epsilon-caroten-3'-ones. Surprisingly, the normal-coloured feathers of the male Pin-tailed Manakin owe their red hue to rhodoxanthin, an unusual carotenoid more commonly found in plants, rather than 4-keto-carotenoids typically found in red plumages and found lacking in previously characterised bird colour variants. The implication is that birds, like the tilapia fish, may be able to synthesise this unusual pigment endogenously from dietary precursors. A newly described carotenoid, 6-hydroxy-epsilon,epsilon-carotene-3,3'-dione, here named piprixanthin, present in the red feathers of the Pin-tailed Manakin, provides a plausible intermediate between epsilon,epsilon-carotene-3,3'-dione (canary-xanthophyll B), a bright yellow pigment found in this and other songbirds, and rhodoxanthin. It is apparent that pigeons (Columbidae, Columbiformes) also have the capability to produce rhodoxanthin, and a structurally related pigment, endogenously. The ability to synthesise rhodoxanthin might have arisen at least twice in birds.
Assuntos
Pigmentação/fisiologia , Aves Canoras/metabolismo , Xantofilas/biossíntese , Animais , Brasil , Columbidae/metabolismo , Dieta , Masculino , Tilápia/metabolismoRESUMO
This study examined the ingestive and behavioral effects of NMDA- and AMPA/kainate glutamatergic receptor blockade in the lateral hypothalamic area (LHy) of free-feeding pigeons (Columba livia). Injections of MK-801 (NMDA receptor antagonist; 6 nmol) or CNQX (AMPA/kainate receptor antagonist; 25.8 nmol) into the LHy of free-feeding pigeons induced significant increases in food intake and in feeding duration, as well as reductions in the latency to start feeding. Duration, latency and volume of water intake, as well as duration of sleep-like behavior, alert immobility, locomotion and preening were not changed by these treatments in the LHy. These results indicate that glutamatergic inputs to cells containing NMDA and/or AMPA receptors located in the LHy could modify both the beginning of a feeding bout (or the end of a period of satiety) and its duration (satiation). Our data also suggest that these inhibitory glutamatergic influences on feeding behavior are tonically active in the LHy.
Assuntos
Columbidae/metabolismo , Comportamento Alimentar/fisiologia , Ácido Glutâmico/metabolismo , Região Hipotalâmica Lateral/metabolismo , Neurônios/metabolismo , Receptores de Glutamato/metabolismo , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/fisiologia , Columbidae/anatomia & histologia , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Região Hipotalâmica Lateral/anatomia & histologia , Região Hipotalâmica Lateral/efeitos dos fármacos , Masculino , Microinjeções/métodos , Inibição Neural/efeitos dos fármacos , Inibição Neural/fisiologia , Vias Neurais/anatomia & histologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Neurônios/efeitos dos fármacos , Terminações Pré-Sinápticas/efeitos dos fármacos , Terminações Pré-Sinápticas/metabolismo , Receptores de AMPA/antagonistas & inibidores , Receptores de AMPA/metabolismo , Receptores de Glutamato/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Resposta de Saciedade/efeitos dos fármacos , Resposta de Saciedade/fisiologia , Especificidade da Espécie , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologiaRESUMO
The uropygial gland is a holocrine secretory gland of birds. The lipid and the waxy sebum that the gland secretes is coated on the beak and transferred to the plumage in preening. The composition of the gland secretions from birds of different species has been determined, but little is known about the lipids of the secretion of the gland of the rock dove Columba livia. The amount of secretion, the total lipid content and the fatty acids composition of the secretion of C. livia captured in the nonbreeding season was reported. The mean amount of the secretion within the gland was 30 mg; the mean lipid content of the secretion was 0.385 mg/mg of secretion, which was equivalent to approximately 38% of the secretion. The weight of the secretion relative to gland weight was 32%. If we assume that the amount of the gland secretion constitutes a valid parameter to determine the degree of the gland development, our results indicate that the physiological role of the gland does not depend upon gland mass (GW); the rock dove in particular has a small gland, but its secretion represented 32% of the gland's mass. The composition of the lipids extracted from the gland secretion consisted of C14 to C20 fatty acids, most of them were unsaturated. The secretion of the gland contained approximately 59% of unsaturated fatty acids with a prevalence of oleic acid (37%) and a low content of linoleic (6%) and arachidonic acids (7%). The saturated long chain fatty acids were mainly 14:0, 16:0 and 18:0 in a percentage of approximately 34%. No sexual differences were found in any of the evaluated parameters.
Assuntos
Columbidae/metabolismo , Glândulas Exócrinas/metabolismo , Metabolismo dos Lipídeos , Lipídeos/química , Animais , Ácido Araquidônico/análise , Ácidos Graxos/análise , Ácidos Graxos Insaturados/análise , Feminino , Ácido Linoleico/análise , Masculino , Ácido Oleico/análiseRESUMO
The distribution of AMPA-type glutamate receptor (GluR) subunits was studied in the Edinger-Westphal nucleus (EW) of chicks and pigeons. GluR1, GluR2, GluR3 and GluR4 subunits appeared to be present in EW neurons of both species, but interspecific differences were observed in the abundance of the different types of subunits found in EW neurons. Of particular note, GluR2 immunoreactivity was present in the vast majority (ca. 80%) of neurons of pigeon EW but was found in only a small fraction (ca. 15%) of chick EW neurons. Scarcity of the GluR2 subunit in chick EW was confirmed by in situ hybridization. Because of the tendency for parvalbumin to be localized to neurons that are selectively deficient in GluR2, we also studied the localization of parvalbumin, as well as other calcium-binding proteins, in EW of chick and pigeon. Parvalbumin was found in more than 50% of chick EW neurons but was not detected in pigeon EW neurons. Our results suggest that there are major glutamatergic inputs to EW neurons in both pigeons and chicks. Furthermore, there are likely to be more AMPA-type calcium-permeable glutamate receptors in EW neurons of chick than in pigeon, since it is known that the subtype containing the edited GluR2 subunit is not calcium permeable.
Assuntos
Química Encefálica/fisiologia , Encéfalo/fisiologia , Galinhas/metabolismo , Columbidae/metabolismo , Parvalbuminas/biossíntese , Receptores de AMPA/biossíntese , Vias Visuais/fisiologia , Animais , Calbindina 2 , Calbindinas , Imuno-Histoquímica , Hibridização In Situ , RNA Mensageiro/biossíntese , Receptores de AMPA/genética , Proteína G de Ligação ao Cálcio S100/metabolismo , Especificidade da EspécieRESUMO
The effects of local injections of adrenaline into the paraventricular nucleus (PVN) and into other anterior hypothalamic areas on blood glucose levels were investigated in conscious pigeons (Columba livia). Adrenaline evoked a reliable and potent increase in blood glucose levels when injected into the PVN; no glycemic change was observed after vehicle injections into the PVN or after adrenaline injections into the 3rd ventricle or hypothalamic structures adjacent to the PVN. Local pretreatment with propranolol, but not with phentolamine, abolished the adrenaline-induced hyperglycemia. The present results indicate that adrenergically mediated circuits into the avian PVN play an important role in central mechanisms of energy balance that may be equivalent to those observed in mammalian species.
Assuntos
Glicemia/metabolismo , Columbidae/metabolismo , Metabolismo Energético/fisiologia , Epinefrina/metabolismo , Vias Neurais/metabolismo , Neurônios/metabolismo , Núcleo Hipotalâmico Paraventricular/metabolismo , Antagonistas Adrenérgicos alfa/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Glicemia/efeitos dos fármacos , Columbidae/anatomia & histologia , Metabolismo Energético/efeitos dos fármacos , Epinefrina/farmacologia , Masculino , Vias Neurais/citologia , Vias Neurais/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacosRESUMO
The effects of intracerebroventricular pretreatment with muscarinic (scopolamine or methylscopolamine; 2.7 nmol or 5.4 nmol) or nicotinic (mecamylamine, 2.7 nmol or 5.4 nmol) cholinergic receptor antagonists on plasma free fatty acid increases induced by intracerebroventricular injections of carbachol in conscious resting pigeons (Columba livia) were examined. Plasma glucose levels were also measured throughout the experiments. Pretreatment with methylscopolamine suppressed the lipolytic effect of carbachol injections, while mecamylamine left this response unchanged. Neither carbachol treatment alone, nor the pretreatments with cholinergic agents affected glucose levels. Subsequently, the effects of intracerebroventricular injections of methylscopolamine were investigated in 24-h food-deprived pigeons. The increase in free fatty acid levels after fasting was of a magnitude similar to that observed after carbachol treatment; intracerebroventricular injections of methylscopolamine (5.4 nmol) transiently but powerfully decreased plasma free fatty acids in 24-h food-deprived pigeons to levels comparable to those of free-feeding animals. The fasting-induced decrease in glucose levels was not affected by this treatment. These data indicate that the lipolytic response induced by carbachol may be mediated by central muscarinic cholinergic receptors and that this central cholinergic mechanism partially contributes to plasma free fatty acid increases observed during fasting. Furthermore, the absence of effects on glucose levels suggests that these cholinergic mechanisms participate selectively in the lipolytic component of the metabolic response to fasting.
Assuntos
Columbidae/metabolismo , Jejum/metabolismo , Ácidos Graxos não Esterificados/sangue , Antagonistas Muscarínicos/farmacologia , Receptores Muscarínicos/metabolismo , Escopolamina/farmacologia , Animais , Glicemia , Carbacol/farmacologia , Agonistas Colinérgicos/farmacologia , Injeções Intraventriculares , Lipólise/efeitos dos fármacos , Lipólise/fisiologia , Masculino , N-Metilescopolamina/farmacologia , Parassimpatolíticos/farmacologiaRESUMO
The possible involvement of central cholinergic neurotransmission in lipomobilization in avian species was investigated by injecting carbachol into the brain lateral ventricle (i.c.v.) of conscious pigeons (N = 9 per experimental group). I.c.v. injections of carbachol (27 nmol in 1 microliter) induced an intense increase (nearly 91% above baseline levels) in the concentration of plasma free fatty acids (FFA). Previous intraperitoneal administration of hexamethonium (10 mg/kg) completely blocked the lipomobilizing effect of i.c.v. injections of carbachol. These results suggest that cholinergic neurons may be involved in central mechanisms controlling FFA mobilization in pigeons, and that this response is mainly mediated by activation of autonomic nervous system.
Assuntos
Sistema Nervoso Autônomo/fisiologia , Carbacol/farmacologia , Agonistas Colinérgicos/farmacologia , Columbidae/metabolismo , Lipólise/fisiologia , Acetilcolina/metabolismo , Animais , Carbacol/administração & dosagem , Agonistas Colinérgicos/administração & dosagem , Antagonistas Colinérgicos/farmacologia , Ácidos Graxos não Esterificados/sangue , Feminino , Hexametônio/farmacologia , Injeções Intraventriculares , Lipólise/efeitos dos fármacos , Masculino , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologiaRESUMO
Immunohistochemical and retrograde tracing techniques were combined in order to identify chemically specific displaced ganglion cells in the pigeon retina. About 15% of the displaced ganglion cells that were retrogradely labeled following injections of different tracers into the accessory optic nucleus were shown to contain cholecystokinin8-like immunoreactivity. These cells were medium to large (15-30 microns) and located mostly in the peripheral retina. Another population of about 9% of the retrogradely labeled displaced ganglion cells was shown to contain leucine-enkephalin-like immunoreactivity. These cells were medium-sized (11-18 microns) and distributed almost evenly throughout the retina. These two types of displaced ganglion cells represent together only about 0.1% of the total number of ganglion cells in the pigeon retina. Taken together with previous results, these data indicate that the displaced ganglion cells of the avian retina may comprise several chemically specific cell types. The present results also contribute information on the chemical heterogeneity of retinal ganglion cells.
Assuntos
Colecistocinina/metabolismo , Columbidae/metabolismo , Encefalina Leucina/metabolismo , Células Ganglionares da Retina/metabolismo , Animais , Colecistocinina/imunologia , Toxina da Cólera/farmacologia , Encefalina Leucina/imunologia , Imuno-Histoquímica , Células Ganglionares da Retina/imunologiaRESUMO
Immunohistochemical and retrograde tracing techniques were combined to demonstrate the occurrence of displaced ganglion cells (DGCs) exhibiting substance P-like immunoreactivity (SP-LI) in the pigeon retina. Following injections of rhodamine-labeled latex microspheres into the nucleus of the basal optic root (accessory optic system), about 5200 DGCs were observed to contain rhodamine fluorescence in the contralateral retina. Approximately 26% of the retrogradely labeled DGCs also contained SP-LI. The soma sizes of the doubly labeled DGCs ranged from 12 to 24 microns, and their distribution mirrored the overall distribution of DGCs projecting to the nucleus of the basal optic root. The density of doubly labeled DGCs ranged from 2 to 15 cells/mm2, with density peaks occurring in the superior-nasal and inferior-temporal retinal quadrants. Larger DGCs projecting to the nBOR (25-32 microns) were never seen to contain SP-LI. Together with previous results of enucleation experiments, these data indicate the existence of a subpopulation of SP-LI DGCs which are connected with the accessory optic system in the pigeon. The present results also contribute information on the heterogeneity of retinal ganglion cells transmitters and modulators.
Assuntos
Columbidae/metabolismo , Células Ganglionares da Retina/metabolismo , Substância P/metabolismo , Animais , Avidina , Biotina , Encéfalo/anatomia & histologia , Imunofluorescência , Imuno-Histoquímica , Microesferas , Retina/anatomia & histologia , Retina/citologia , Células Ganglionares da Retina/imunologia , Rodaminas , Substância P/imunologiaRESUMO
No presente trabalho os autores analisam comparativamente aspectos do controle do metabolismo lipídico no pombo, discutindo relatos da literatura com os dados obtidos em suas experiências
Assuntos
Animais , Masculino , Feminino , Ácidos Graxos/metabolismo , Columbidae/metabolismo , Lipídeos/metabolismo , Pâncreas/metabolismo , Sistema Hipófise-SuprarrenalRESUMO
By means of starch gel electrophoresis and specific staining, molecular forms of aspartate aminotransferase and soluble esterases have been investigated in liver extracts of individuals from a population of Zenaida auriculata. Four alleles at the locus corresponding to soluble or cytoplasmic aspartate aminotransferase have been demonstrated. Distribution of phenotypes in the population is in perfect agreement with that expected according to the Hardy - Weinberg law. A large incidence of variants of two fractions of esterases has been found. This variability is, with all probability, genetically determined. The importance of this type of studies to assess genetic structure and dynamics of animal population is emphasized.