RESUMEN
The stress experienced during rape seems to facilitate ovulation since the pregnancy rate in raped women is higher than that resulting from consensual intercourse. Adrenal progesterone, as well as central norepinephrine, is released in stressful situations. At adequate estrogenic levels, one of the main actions of progesterone is to anticipate the preovulatory LH surge through noradrenaline release. We aimed to investigate whether acute stresses that mimic those of rape (exposure to predator, restraint and cervix stimulation) applied on the proestrus morning in female rats could release progesterone, activate the noradrenergic neurons and facilitate the occurrence of the LH surge. Female rats were submitted to jugular vein cannulation immediately following acute stress: restraint (R), exposure to cat (P), uterine cervix stimulation (CS) applied individually or in association (SA). Non-stressed rats were used as control. Blood samples were collected from 11:00-18:00 h for LH, progesterone, corticosterone and estradiol measurements. Double labeling for c-Fos and tyrosine hydroxylase (TH) was examined in A1, A2 and A6 noradrenergic neurons after stresses. The SA group showed a greater stress-induced increase in progesterone compared to the other groups and the preovulatory LH surge was anticipated and amplified. This effect of SA seems to be related to the higher number of c-Fos/TH + neurons in the A1 and A2. The effect of anticipating the preovulatory surge of LH could in part elucidate why, in raped women, conception can occur in phases of the menstrual cycle other than the ovulatory phase facilitating the occurrence of pregnancies.
Asunto(s)
Neuronas Adrenérgicas , Progesterona , Animales , Estradiol/farmacología , Femenino , Humanos , Hormona Luteinizante , Norepinefrina , Ovulación , Embarazo , Progesterona/farmacología , Ratas , Tirosina 3-MonooxigenasaRESUMEN
Neonatal handling induces several behavioral and neurochemical alterations in pups, including decreased responses to stress and reduced fear in new environments. However, there are few reports in the literature concerning the behavioral effects of this neonatal intervention on the dams during the postpartum period. Therefore, the aim of the current study was to determine if brief postpartum separation from pups has a persistent impact on the dam's stress response and behavior. Litters were divided into two neonatal groups: 1) non-handled and 2) handled [10â min/day, from postnatal day (PND) 1 to 10]. Weaning occurred at PND 21 when behavioral tasks started to be applied to the dams, including sweet food ingestion (PND 21), forced swimming test (PND 28), and locomotor response to a psychostimulant (PND 28). On postpartum day 40, plasma was collected at baseline for leptin assays and after 1â h of restraint for corticosterone assay. Regarding sweet food consumption, behavior during the forced swimming test or plasma leptin levels did not differ between dams briefly separated and non-separated from their pups during the postpartum period. On the other hand, both increased locomotion in response to diethylpropion and increased corticosterone secretion in response to acute stress were detected in dams briefly separated from their pups during the first 10 postnatal days. Taken together, these findings suggest that brief, repeated separations from the pups during the neonatal period persistently impact the behavior and induce signs of dopaminergic sensitization in the dam.
Asunto(s)
Animales Recién Nacidos , Corticosterona/sangre , Leptina/sangre , Privación Materna , Actividad Motora/fisiología , Estrés Psicológico/fisiopatología , Animales , Animales Recién Nacidos/sangre , Femenino , Humanos , Masculino , Embarazo , Ratas Wistar , Estrés Psicológico/sangre , Natación , Factores de TiempoRESUMEN
Neonatal handling induces several behavioral and neurochemical alterations in pups, including decreased responses to stress and reduced fear in new environments. However, there are few reports in the literature concerning the behavioral effects of this neonatal intervention on the dams during the postpartum period. Therefore, the aim of the current study was to determine if brief postpartum separation from pups has a persistent impact on the dam's stress response and behavior. Litters were divided into two neonatal groups: 1) non-handled and 2) handled [10 min/day, from postnatal day (PND) 1 to 10]. Weaning occurred at PND 21 when behavioral tasks started to be applied to the dams, including sweet food ingestion (PND 21), forced swimming test (PND 28), and locomotor response to a psychostimulant (PND 28). On postpartum day 40, plasma was collected at baseline for leptin assays and after 1 h of restraint for corticosterone assay. Regarding sweet food consumption, behavior during the forced swimming test or plasma leptin levels did not differ between dams briefly separated and non-separated from their pups during the postpartum period. On the other hand, both increased locomotion in response to diethylpropion and increased corticosterone secretion in response to acute stress were detected in dams briefly separated from their pups during the first 10 postnatal days. Taken together, these findings suggest that brief, repeated separations from the pups during the neonatal period persistently impact the behavior and induce signs of dopaminergic sensitization in the dam.
Asunto(s)
Animales , Femenino , Humanos , Masculino , Embarazo , Animales Recién Nacidos , Corticosterona/sangre , Leptina/sangre , Privación Materna , Actividad Motora/fisiología , Estrés Psicológico/fisiopatología , Animales Recién Nacidos/sangre , Ratas Wistar , Natación , Estrés Psicológico/sangre , Factores de TiempoRESUMEN
Infant rats must learn to identify their mother’s diet-dependent odor. Once learned, maternal odor controls pups’ approach to the mother, their social behavior and nipple attachment. Here we present a review of the research from four different laboratories, which suggests that neural and behavioral responses to the natural maternal odor and neonatal learned odors are similar. Together, these data indicate that pups have a unique learning circuit relying on the olfactory bulb for neural plasticity and on the hyperfunctioning noradrenergic locus coeruleus flooding the olfactory bulb with norepinephrine to support the neural changes. Another important factor making this system unique is the inability of the amygdala to become incorporated into the infant learning circuit. Thus, infant rats appear to be primed in early life to learn odors that will evoke approach responses supporting attachment to the caregiver.
Asunto(s)
Animales , Femenino , Ratas , Amígdala del Cerebelo/fisiología , Señales (Psicología) , Aprendizaje Discriminativo/fisiología , Conducta Alimentaria/fisiología , Locus Coeruleus/fisiología , Odorantes , Bulbo Olfatorio/fisiología , Animales Recién Nacidos , Plasticidad Neuronal/fisiología , Norepinefrina/fisiologíaRESUMEN
Infant rats must learn to identify their mother's diet-dependent odor. Once learned, maternal odor controls pups' approach to the mother, their social behavior and nipple attachment. Here we present a review of the research from four different laboratories, which suggests that neural and behavioral responses to the natural maternal odor and neonatal learned odors are similar. Together, these data indicate that pups have a unique learning circuit relying on the olfactory bulb for neural plasticity and on the hyperfunctioning noradrenergic locus coeruleus flooding the olfactory bulb with norepinephrine to support the neural changes. Another important factor making this system unique is the inability of the amygdala to become incorporated into the infant learning circuit. Thus, infant rats appear to be primed in early life to learn odors that will evoke approach responses supporting attachment to the caregiver.
Asunto(s)
Amígdala del Cerebelo/fisiología , Señales (Psicología) , Aprendizaje Discriminativo/fisiología , Conducta Alimentaria/fisiología , Locus Coeruleus/fisiología , Odorantes , Bulbo Olfatorio/fisiología , Animales , Animales Recién Nacidos , Femenino , Plasticidad Neuronal/fisiología , Norepinefrina/fisiología , RatasRESUMEN
Neonatal handling in rats persistently alters behavioral parameters and responses to stress. Such animals eat more sweet food in adult life, without alterations in lab chow ingestion. Here, we show that neonatally handled rats display greater incentive salience to a sweet reward in a runway test; however they are less prone to conditioned place preference and show less positive hedonic reactions to sweet food. When injected with methylphenidate (a dopamine mimetic agent), non-handled rats increase their sweet food ingestion in the fasted state, while neonatally handled rats do not respond. We did not observe any differences regarding baseline general ambulatory activity between the groups. A lower dopamine metabolism in the nucleus accumbens was observed in handled animals, without differences in norepinephrine content. We suggest that early handling leads to a particular response to positive reinforcers such as palatable food, in a very peculiar fashion of higher ingestion but lower hedonic impact, as well as higher incentive salience, but diminished dopaminergic metabolism in the nucleus accumbens.
Asunto(s)
Dopamina/metabolismo , Conducta Alimentaria/fisiología , Núcleo Accumbens/fisiopatología , Estrés Psicológico/fisiopatología , Envejecimiento , Animales , Animales Recién Nacidos , Condicionamiento Clásico/fisiología , Dieta , Inhibidores de Captación de Dopamina/farmacología , Ayuno , Conducta Alimentaria/efectos de los fármacos , Masculino , Metilfenidato/farmacología , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Norepinefrina/metabolismo , Ratas , Ratas Wistar , Recompensa , Percepción Espacial/fisiologíaRESUMEN
Early-life environmental events, such as the handling procedure, can induce long-lasting alterations upon several behavioral and neuroendocrine systems. However, the changes within the pups that could be causally related to the effects in adulthood are still poorly understood. In the present study, we analyzed the effects of neonatal handling on behavioral (maternal odor preference) and biochemical (cyclic AMP response element-binding protein (CREB) phosphorylation, noradrenaline (NA), and serotonin (5-HT) levels in the olfactory bulb (OB)) parameters in 7-day-old male and female rat pups. Repeated handling (RH) abolished preference for the maternal odor in female pups compared with nonhandled (NH) and the single-handled (SH) ones, while in RH males the preference was not different than NH and SH groups. In both male and female pups, RH decreased NA activity in the OB, but 5-HT activity increased only in males. Since preference for the maternal odor involves the synergic action of NA and 5-HT in the OB, the maintenance of the behavior in RH males could be related to the increased 5-HT activity, in spite of reduction in the NA activity in the OB. RH did not alter CREB phosphorylation in the OB of both male and females compared with NH pups. The repeated handling procedure can affect the behavior of rat pups in response to the maternal odor and biochemical parameters related to the olfactory learning mechanism. Sex differences were already detected in 7-day-old pups. Although the responsiveness of the hypothalamic-pituitary-adrenal axis to stressors is reduced in the neonatal period, environmental interventions may impact behavioral and biochemical mechanisms relevant to the animal at that early age.
Asunto(s)
Monoaminas Biogénicas/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Manejo Psicológico , Conducta Materna , Odorantes , Bulbo Olfatorio/metabolismo , Análisis de Varianza , Animales , Animales Recién Nacidos , Cromatografía Líquida de Alta Presión/métodos , Condicionamiento Psicológico , Electroquímica/métodos , Femenino , Masculino , Embarazo , Ratas , Ratas Wistar , Factores Sexuales , Transducción de Señal/fisiologíaRESUMEN
We have reported that neonatal handling leads to increased sweet food preference in adult life. Our aim was to verify if these differences in feeding behavior appear before puberty, and whether other types of intervention in periadolescence (such as exposure to toys) could interfere with sweet food consumption later in life. Nests of Wistar rats were (1) non-handled or (2) handled (10 min/day) on days 1-10 after birth. Males from these groups were subdivided in two subgroups: one was habituated to sweet food (Froot Loops-Kellogs) in a new environment for 4 days and tested for sweet food preference at age 27 days, before submitting to a new habituation and test for sweet food ingestion again in adult life. The other subgroup was habituated and tested only in adulthood. In another set of experiments, neonatally non-handled rats were exposed or not to a new environment with toys in periadolescence, and tested for sweet food ingestion as adults. Neonatal handling increases sweet food consumption only if the habituation and tests are performed after puberty. Interestingly, infant exposure to sweet food had a similar effect as neonatal handling, since controls that were exposed to sweet food at age 22 to 27 days increased their ingestion as adults. Exposure to toys in periadolescence had the same effect. We suggest that an intervention during the first postnatal days or exposure to an enriched environment later in the pre-pubertal period leads to behavioral alterations that persist through adulthood, such as increased sweet food ingestion.
Asunto(s)
Ingestión de Alimentos/psicología , Conducta Alimentaria/fisiología , Preferencias Alimentarias/fisiología , Manejo Psicológico , Animales , Animales Recién Nacidos , Conducta Animal , Femenino , Habituación Psicofisiológica/fisiología , Masculino , Estimulación Física , Embarazo , Ratas , Ratas WistarRESUMEN
Serotonin (5-HT1B) receptors play an essential role in the inhibition of aggressive behavior in rodents. CP-94,253, a 5-HT1B receptor agonist, can reduce aggression in male mice when administered directly into the ventro-orbitofrontal (VO) prefrontal cortex (PFC). The objective of the current study was to assess the effects of two selective 5-HT1B receptor agonists (CP-94,253 and CP-93,129), microinjected into the VO PFC, on maternal aggressive behavior after social instigation in rats. CP-94,253 (0.56 microg/0.2 microL, N = 8, and 1.0 microg/0.2 microL, N = 8) or CP-93,129 (1.0 microg/0.2 microL, N = 9) was microinjected into the VO PFC of Wistar rats on the 9th day postpartum and 15 min thereafter the aggressive behavior by the resident female against a male intruder was recorded for 10 min. The frequency and duration of aggressive and non-aggressive behaviors were analyzed using ANOVA and post hoc tests. CP-93,129 significantly decreased maternal aggression. The frequency of lateral attacks, bites and pinnings was reduced compared to control, while the non-aggressive behaviors and maternal care were largely unaffected by this treatment. CP-94,253 had no significant effects on aggressive or non-aggressive behaviors when microinjected into the same area of female rats. CP-93,129, a specific 5-HT1B receptor agonist, administered into the VO PFC reduced maternal aggressive behavior, while the CP-94,253 agonist did not significantly affect this behavior after social instigation in female rats. We conclude that only the 5-HT1B receptor agonist CP-93,129 administered into the VO PFC decreased aggression in female rats postpartum after social instigation.
Asunto(s)
Agresión/efectos de los fármacos , Conducta Materna/efectos de los fármacos , Piridinas/administración & dosificación , Pirroles/administración & dosificación , Receptor de Serotonina 5-HT1B/efectos de los fármacos , Agonistas de Receptores de Serotonina/administración & dosificación , Animales , Conducta Animal/efectos de los fármacos , Femenino , Masculino , Microinyecciones , Corteza Prefrontal/efectos de los fármacos , Piridinas/farmacología , Pirroles/farmacología , Ratas , Ratas Wistar , Agonistas de Receptores de Serotonina/farmacologíaRESUMEN
Serotonin (5-HT1B) receptors play an essential role in the inhibition of aggressive behavior in rodents. CP-94,253, a 5-HT1B receptor agonist, can reduce aggression in male mice when administered directly into the ventro-orbitofrontal (VO) prefrontal cortex (PFC). The objective of the current study was to assess the effects of two selective 5-HT1B receptor agonists (CP-94,253 and CP-93,129), microinjected into the VO PFC, on maternal aggressive behavior after social instigation in rats. CP-94,253 (0.56 µg/0.2 µL, N = 8, and 1.0 µg/0.2 µL, N = 8) or CP-93,129 (1.0 µg/0.2 µL, N = 9) was microinjected into the VO PFC of Wistar rats on the 9th day postpartum and 15 min thereafter the aggressive behavior by the resident female against a male intruder was recorded for 10 min. The frequency and duration of aggressive and non-aggressive behaviors were analyzed using ANOVA and post hoc tests. CP-93,129 significantly decreased maternal aggression. The frequency of lateral attacks, bites and pinnings was reduced compared to control, while the non-aggressive behaviors and maternal care were largely unaffected by this treatment. CP-94,253 had no significant effects on aggressive or non-aggressive behaviors when microinjected into the same area of female rats. CP-93,129, a specific 5-HT1B receptor agonist, administered into the VO PFC reduced maternal aggressive behavior, while the CP-94,253 agonist did not significantly affect this behavior after social instigation in female rats. We conclude that only the 5-HT1B receptor agonist CP-93,129 administered into the VO PFC decreased aggression in female rats postpartum after social instigation.
Asunto(s)
Animales , Femenino , Masculino , Ratas , Agresión/efectos de los fármacos , Conducta Materna/efectos de los fármacos , Piridinas/administración & dosificación , Pirroles/administración & dosificación , /efectos de los fármacos , Agonistas de Receptores de Serotonina/administración & dosificación , Conducta Animal/efectos de los fármacos , Microinyecciones , Corteza Prefrontal/efectos de los fármacos , Piridinas/farmacología , Pirroles/farmacología , Ratas Wistar , Agonistas de Receptores de Serotonina/farmacologíaRESUMEN
Neonatal handled rats ingest more sweet food than non-handled ones, but it was documented only after puberty. Here, we studied the purinergic system in the nucleus accumbens, a possible target for the alteration in the preference for palatable food. We measured the ATP, ADP and AMP hydrolysis mediated by ectonucleotidases in synaptosomes of the nucleus accumbens in periadolescent and adult rats from different neonatal environments: non-handled and handled (10 min/day, first 10 days of life). Before adolescence, we found a decreased ingestion of sweet food in the neonatally handled group, with no effect on ATP, ADP or AMP hydrolysis. In adults, we found a greater ingestion of sweet food in the neonatally handled group, with no effect on ATPase or ADPase activities, but a decreased AMP hydrolysis. The nucleus accumbens is a site of intensive interaction between the adenosinergic and dopaminergic systems. Therefore, adenosine may modulate accumbens' dopamine neurotransmission differently in neonatally handled rats.
Asunto(s)
Envejecimiento/fisiología , Animales Recién Nacidos , Sacarosa en la Dieta , Ingestión de Alimentos , Manejo Psicológico , Nucleotidasas/metabolismo , Núcleo Accumbens/enzimología , Animales , Femenino , Masculino , Monoéster Fosfórico Hidrolasas , Embarazo , RatasRESUMEN
Neonatal handling induces anovulatory estrous cycles and decreases sexual receptivity in female rats. The synchronous secretion of hormones from the gonads (estradiol (E2) and progesterone (P)), pituitary (luteinizing (LH) and follicle-stimulating (FSH) hormones) and hypothalamus (LH-releasing hormone (LHRH)) are essential for the reproductive functions in female rats. The present study aimed to describe the plasma levels of E2 and P throughout the estrous cycle and LH, FSH and prolactin (PRL) in the afternoon of the proestrus, and the LHRH content in the medial preoptic area (MPOA), median eminence (ME) and medial septal area (MSA) in the proestrus, in the neonatal handled rats. Wistar pup rats were handled for 1 min during the first 10 days after delivery (neonatal handled group) or left undisturbed (nonhandled group). When they reached adulthood, blood samples were collected through a jugular cannula and the MPOA, ME and MSA were microdissected. Plasma levels of the hormones and the content of LHRH were determined by RIA. The number of oocytes counted in the morning of the estrus day in the handled rats was significantly lower than in the nonhandled ones. Neonatal handling reduces E2 levels only on the proestrus day while P levels decreased in metestrus and estrus. Handled females also showed reduced plasma levels of LH, FSH and PRL in the afternoon of the proestrus. The LHRH content in the MPOA was significantly higher than in the nonhandled group. The reduced secretion of E2, LH, FSH and LHRH on the proestrus day may explain the anovulatory estrous cycle in neonatal handled rats. The reduced secretion of PRL in the proestrus may be related to the decreased sexual receptiveness in handled females. In conclusion, early-life environmental stimulation can induce long-lasting effects on the hypothalamus-pituitary-gonad axis.
Asunto(s)
Animales Recién Nacidos/fisiología , Manejo Psicológico , Reproducción/fisiología , Animales , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Hormona Liberadora de Gonadotropina/análisis , Hormona Luteinizante/sangre , Eminencia Media/química , Área Preóptica/química , Proestro/sangre , Progesterona/sangre , Prolactina/sangre , Radioinmunoensayo/métodos , Ratas , Ratas Wistar , Tabique del Cerebro/químicaRESUMEN
Adverse early life events may influence vulnerability for drug intake. The influence of handling or aversive stimulation during neonatal or adolescent periods on adult cocaine oral self-administration and withdrawal were investigated. Neonatal or adolescent rats were exposed to a modified unpredictable stress paradigm or handling for 10 days. When adults, oral cocaine was offered through the two-bottle choice paradigm for 30 days. Rats were submitted to the forced swimming test after cocaine withdrawal. Overall, there was a significant increase of cocaine choice throughout the days of cocaine consumption and an interaction between interventions and cocaine daily choice. Control rats started cocaine intake at a lower level and increased cocaine choice over time, while animals submitted to neonatal interventions started cocaine intake at higher levels of choice, with less increase in cocaine intake during the period of cocaine exposure. Rats receiving aversive stimulation during adolescence also started taking cocaine solution at higher levels. Significantly higher immobility duration and shorter latency to immobility during the forced swimming were detected in these same adolescents that received unpredictable stress, when compared to the control or handled rats, while there was no difference for rats stimulated neonatally. Therefore, early life events increase initial preference for cocaine and promote changes in its abuse pattern, according to the intensity of the event and the age of the individual at the time of the event. Moreover, adverse experiences during adolescence, but not in neonatal phases, increase the vulnerability to depressive-like behaviors during cocaine withdrawal of adult rats.
Asunto(s)
Trastornos Relacionados con Cocaína/fisiopatología , Cocaína/efectos adversos , Cocaína/farmacología , Inhibidores de Captación de Dopamina/efectos adversos , Inhibidores de Captación de Dopamina/farmacología , Estrés Psicológico , Adolescente , Factores de Edad , Animales , Animales Recién Nacidos , Cocaína/administración & dosificación , Depresión , Modelos Animales de Enfermedad , Inhibidores de Captación de Dopamina/administración & dosificación , Femenino , Humanos , Masculino , Condicionamiento Físico Animal , Ratas , Ratas Wistar , Factores de Riesgo , Síndrome de Abstinencia a SustanciasRESUMEN
Stress during the neonatal period leads to a large number of behavioral and biochemical alterations in adult life. The aim of this study is to verify the effects of handling and tactile stimulation during the first 10 days of life on feeding behavior in adult rats. Litters were divided into (1). intact; (2). handled (10 min/day); and (3). handled and tactile stimulated (10 min/day). Procedures were performed on Days 1-10 after birth. When adults, rats were tested for ingestion of sweet and savory snacks. We also measured body weight, ingestion of standard lab chow, and consumption of water and 1% glucose and 1.5% NaCl solutions. Stressed rats (handling and handling+tactile stimulation groups) consumed more sweet (two-way ANOVA, P=.008) or savory snacks (P=.001) than intact ones. This effect was observed in males and females. There were no differences in body weight, ingestion of standard lab chow, water, or in the ingestion of sweetened or salty solutions between groups. The same animals were tested later in life (15 months of age), and the effect was still evident. We suggest that handling during the neonatal period leads to alterations in the CNS of rats, causing an increased ingestion of palatable food in adult life, and this alteration probably persists throughout the whole life.
Asunto(s)
Animales Recién Nacidos/psicología , Apetito/fisiología , Conducta Alimentaria/fisiología , Manejo Psicológico , Estrés Psicológico/fisiopatología , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos/fisiología , Conducta Alimentaria/psicología , Femenino , Masculino , Embarazo , Ratas , Ratas Wistar , Gusto/fisiología , Tacto/fisiologíaRESUMEN
Research was undertaken to study the role of central angiotensin in the modulation of male sexual behavior, testing the effect of angiotensin II (Ang II) injections into the medial amygdaloid nucleus (MeA). The sexual behavior of adult male Wistar rats was evaluated, 15 min after bilateral intra-amygdaloid microinjection (0.3 microl) of saline and 5 doses of Ang II: 10; 25; 50; 100, and 150 fmol. The effects of the Ang II receptor blockade were also studied. We tested the effect of coinjection of Ang II (50 fmol) with the AT1 antagonist, losartan (20 pmol) and the AT2 antagonist, CGP 42112 (1 pmol). Ang II inhibited sexual behavior and this inhibition was prevented by the coinjection of AT1 antagonist, losartan, or the AT2 antagonist, CGP 42112. Results show that Ang II has a powerful effect on male sexual behavior, which may be mediated by both AT1 and AT2 receptors.
Asunto(s)
Amígdala del Cerebelo/efectos de los fármacos , Angiotensina II/farmacología , Conducta Sexual Animal/efectos de los fármacos , Vasoconstrictores/farmacología , Amígdala del Cerebelo/fisiología , Antagonistas de Receptores de Angiotensina , Animales , Antihipertensivos/farmacología , Losartán/farmacología , Masculino , Microinyecciones , Oligopéptidos/farmacología , Ratas , Ratas Wistar , Receptor de Angiotensina Tipo 1 , Receptor de Angiotensina Tipo 2RESUMEN
This article is a transcription of an electronic symposium held on November 28, 2000 in which active researchers were invited by the Brazilian Society of Neuroscience and Behavior (SBNeC) to discuss the advances of the last decade in the peptide field with particular focus on central actions of prolactin and cholecystokinin. The comments in this symposium reflect the diversity of prolactin and cholecystokinin research and demonstrate how the field has matured. Since both peptides play a role in reproductive behaviors, particularly mother-infant interactions, this was the starting point of the discussion. Recent findings on the role of the receptor subtypes as well as interaction with other peptides in this context were also discussed. Another issue discussed was the possible role of these peptides in dopamine-mediated rewarding systems. Both prolactin and cholecystokinin are involved in mechanisms controlling food intake and somatic pain thresholds. The role of peripheral inputs through vagal afferents modulating behavior was stressed. The advent of knockout animals as potential generators of new knowledge in this field was also addressed. Finally, interactions with other neuropeptides and investigation of the role of these peptides in other fields such as immunology were mentioned. Knowledge about the central functions of prolactin and cholecystokinin has shown important advances. The role of these peptides in neurological and psychiatric syndromes such as anorexia, drug abuse and physiological disturbances that lead to a compromised maternal behavior seems relevant
Asunto(s)
Humanos , Femenino , Cerebro/fisiología , Colecistoquinina , Prolactina , Internet , Conducta MaternaRESUMEN
This article is a transcription of an electronic symposium held on November 28, 2000 in which active researchers were invited by the Brazilian Society of Neuroscience and Behavior (SBNeC) to discuss the advances of the last decade in the peptide field with particular focus on central actions of prolactin and cholecystokinin. The comments in this symposium reflect the diversity of prolactin and cholecystokinin research and demonstrate how the field has matured. Since both peptides play a role in reproductive behaviors, particularly mother-infant interactions, this was the starting point of the discussion. Recent findings on the role of the receptor subtypes as well as interaction with other peptides in this context were also discussed. Another issue discussed was the possible role of these peptides in dopamine-mediated rewarding systems. Both prolactin and cholecystokinin are involved in mechanisms controlling food intake and somatic pain thresholds. The role of peripheral inputs through vagal afferents modulating behavior was stressed. The advent of knockout animals as potential generators of new knowledge in this field was also addressed. Finally, interactions with other neuropeptides and investigation of the role of these peptides in other fields such as immunology were mentioned. Knowledge about the central functions of prolactin and cholecystokinin has shown important advances. The role of these peptides in neurological and psychiatric syndromes such as anorexia, drug abuse and physiological disturbances that lead to a compromised maternal behavior seems relevant.
Asunto(s)
Encéfalo/fisiología , Colecistoquinina/fisiología , Prolactina/fisiología , Femenino , Humanos , Internet , Conducta Materna/fisiologíaRESUMEN
Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-æm sections at 120-æm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 + or - 206, N = 6; 1020 + or - 150, N = 6; nonhandled and handled, respectively), paraventricular (584 + or - 85, N = 8; 682 + or - 62, N = 9) or periventricular (743 + or - 118, N = 7; 990 + or - 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain
Asunto(s)
Animales , Masculino , Femenino , Ratas , Conducta Animal/fisiología , Manejo Psicológico , Hipotálamo Anterior/fisiología , Neuronas/fisiología , Tirosina 3-Monooxigenasa/metabolismo , Animales Recién Nacidos , Núcleo Hipotalámico Anterior/enzimología , Núcleo Hipotalámico Anterior/fisiología , Dopamina/fisiología , Hipotálamo Anterior/enzimología , Neuronas/inmunología , Estimulación Física , Ratas Wistar , Estrés Psicológico , Tirosina 3-Monooxigenasa/inmunologíaRESUMEN
Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-microm sections at 120-microm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 +/- 206, N = 6; 1020 +/- 150, N = 6; nonhandled and handled, respectively), paraventricular (584 +/- 85, N = 8; 682 +/- 62, N = 9) or periventricular (743 +/- 118, N = 7; 990 +/- 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain.
Asunto(s)
Conducta Animal/fisiología , Manejo Psicológico , Hipotálamo Anterior/fisiología , Neuronas/fisiología , Tirosina 3-Monooxigenasa/metabolismo , Animales , Animales Recién Nacidos , Núcleo Hipotalámico Anterior/enzimología , Núcleo Hipotalámico Anterior/fisiología , Dopamina/fisiología , Femenino , Hipotálamo Anterior/enzimología , Masculino , Neuronas/inmunología , Estimulación Física , Ratas , Ratas Wistar , Estrés Psicológico , Tirosina 3-Monooxigenasa/inmunologíaRESUMEN
The present study aimed to analyze the effects of neonatal stimulation on species-specific behaviors (defensive reactions to a predator and social interactions) in adult male and female rats. Handling and an unpredictable sequence of aversive stimuli were applied to male and female pups from the 1st to the 10th day after delivery; behavioral inhibition, aggression, and sexual behavior were evaluated in adulthood. Results showed that either neonatal handling or aversive stimulation decreased behavioral inhibition in a novel and potentially harmful situation (open field with a predator) in both male and female rats and increased maternal aggressive behavior. Sexual behavior in both males and females decreased, which could affect reproductive capability. The results could cast doubts on the generalization of beneficial effects of neonatal stimulation on the behavior of adult rats.