RESUMEN
The distribution of the kappa opioid receptor mRNA in adult mouse brain has been determined using the technique of in situ hybridization histochemistry. The mRNA for the kappa opioid receptor was expressed in distinct areas throughout the brain. The telencephalon showed high levels of expression in the deeper layers of the parietal and temporal cortex, olfactory tubercle, nucleus accumbens, claustrum, endopiriform nucleus, nucleus of the vertical and horizontal limb of the diagonal band, and medial and central nuclei of the amygdala. In the diencephalon, kappa opioid receptor mRNA was present in multiple medial thalamic nuclei including the centromedial, paraventricular, parafasicular, central, and peritenial nuclei, as well as in most hypothalamic nuclei including the ventromedial, periventricular, supraoptic, arcuate, and dorsomedial nuclei. The mesencephalon showed highest levels of kappa receptor mRNA in the substantia nigra pars compacta, ventral tegmental area, zona incerta, interpeduncular nucleus, superior colliculus, inferior colliculus, central grey, and the raphe nucleus. In the metencephalon, kappa opioid receptor mRNA was expressed in the parabrachial nuclei, locus coeruleus, dorsal and ventral tegmental nuclei, and the raphe pontine nuclei. The distribution of the kappa receptor mRNA closely coincides with the localization of binding sites in rat brain for [3H]U-69,593, a specific kappa 1 opioid receptor ligand. The mRNA distribution also correlates with neuroanatomical sites of actions of kappa agonists and distribution of the endogenous kappa receptor ligand dynorphin.
Asunto(s)
Química Encefálica , Receptores Opioides kappa/genética , Animales , Dinorfinas/análisis , Hibridación in Situ , Masculino , Ratones , Ratones Endogámicos C57BL , Especificidad de Órganos , ARN Mensajero/análisis , Receptores Opioides kappa/biosíntesisRESUMEN
The anterograde and retrograde transport of horseradish peroxidase was used to study the anatomical organization of visceral and limbic terminal fields in the insular cortex. Following injections into the ventroposterolateral parvicellular (VPLpc) and ventroposteromedial parvicellular (VPMpc) visceral relay nuclei of the thalamus, dense anterograde and retrograde labeling was present in the posterior granular and dysgranular insular cortices, respectively. The parabrachial nucleus had extensive connections with the posterior dysgranular cortex and to a lesser degree with the anterior dysgranular and granular cortices. In contrast, injections into the medial prefrontal cortex and mediodorsal nucleus of the thalamus resulted in dense anterograde and retrograde labeling primarily in the anterior agranular cortex, whereas injections in the amygdala resulted in axonal labeling in the agranular and dysgranular insular cortices. Injections into the lateral hypothalamic area resulted in dense anterograde and retrograde labeling mainly in the agranular and dysgranular cortices and moderate to light labeling in the granular cortex. Our results indicate that ascending visceral afferents, VPLpc, VPMpc, and parabrachial nuclei, are topographically organized in the granular and dysgranular fields of the insular cortex, whereas the agranular cortex appears to receive highly integrated limbic afferents from the infralimbic cortex and the mediodorsal nucleus of the thalamus. Although these visceral and limbic inputs to the insular cortex are segregated for the most part into different longitudinally oriented strips of cortex, limbic input from the lateral hypothalamic area and the amygdala, which have extensive autonomic as well as limbic connections, are more diffusely distributed over the different regions of the insular cortex. This organization may subserve a role for the insular cortex in integration of autonomic response with ongoing behaviour and emotion.
Asunto(s)
Vías Aferentes/anatomía & histología , Amígdala del Cerebelo/anatomía & histología , Corteza Cerebral/anatomía & histología , Vías Eferentes/anatomía & histología , Sistema Límbico/anatomía & histología , Ratas/anatomía & histología , Tálamo/anatomía & histología , Animales , Transporte Axonal , Peroxidasa de Rábano Silvestre , Área Hipotalámica Lateral/anatomía & histología , Aglutinina del Germen de Trigo-Peroxidasa de Rábano Silvestre Conjugada , Aglutininas del Germen de TrigoRESUMEN
We recently demonstrated that porcine brain natriuretic peptide-like immunoreactive (pBNPir) fibers innervate parts of the cardiovascular system, including the arteries comprising the circle of Willis. To determine the origin of this innervation, we used the retrograde fluorescent tracer Fast Blue dye combined with pBNP immunocytochemistry. Cells which project to the middle cerebral artery and were also pBNPir were found in the trigeminal, pterygopalatine and superior cervical ganglia bilaterally but not in the geniculate or otic ganglia. The majority of these double-labelled cells were found in the ipsilateral trigeminal (46%) and superior cervical ganglia (34%). A pBNP-like substance may be a natural vasodilator in sympathetic, sensory and to a lesser extent parasympathetic neurons innervating the cerebrovascular system.
Asunto(s)
Factor Natriurético Atrial/fisiología , Química Encefálica/fisiología , Arterias Cerebrales/inervación , Amidinas , Animales , Ganglios/citología , Inmunoquímica , Inmunohistoquímica , Masculino , Neuronas Aferentes/fisiología , Ratas , Ratas Endogámicas , PorcinosRESUMEN
On the basis of stimulation studies, it has been proposed that the infralimbic cortex (ILC), Brodmann area 25, may serve as an autonomic motor cortex. To explore this hypothesis, we have combined anterograde tracing with Phaseolus vulgaris leucoagglutinin (PHA-L) and retrograde tracing with wheat germ aggutinin conjugated to horseradish peroxidase (WGA-HRP) to determine the efferent projections from the ILC. Axons exit the ILC in one of three efferent pathways. The dorsal pathway ascends through layers III and V to innervate the prelimbic and anterior cingulate cortices. The lateral pathway courses through the nucleus accumbens to innervate the insular cortex, the perirhinal cortex, and parts of the piriform cortex. In addition, some fibers from the lateral pathway enter the corticospinal tract. The ventral pathway is by far the largest and innervates the thalamus (including the paraventricular nucleus of the thalamus, the border zone between the paraventricular and medial dorsal nuclei, and the paratenial, reuniens, ventromedial, parafasicular, and subparafasicular nuclei), the hypothalamus (including the lateral hypothalamic and medial preoptic areas, and the suprachiasmatic, dorsomedial, and supramammillary nuclei), the amygdala (including the central, medial, and basomedial nuclei, and the periamygdaloid cortex) and the bed nucleus of the stria terminalis. The ventral efferent pathway also provides descending projections to autonomic cell groups of the brainstem and spinal cord including the periaqueductal gray matter, the parabrachial nucleus, the nucleus of the solitary tract, the dorsal motor vagal nucleus, the nucleus ambiguus, and the ventrolateral medulla, as well as lamina I and the intermediolateral column of the spinal cord. The ILC has extensive projections to central autonomic nuclei that may subserve a role in modulating visceral responses to emotional stimuli, such as stress.
Asunto(s)
Sistema Nervioso Autónomo/anatomía & histología , Corteza Cerebral/anatomía & histología , Ratas/anatomía & histología , Animales , Transporte Axonal , Mapeo Encefálico , Vías Eferentes/anatomía & histología , Lectinas , Sistema Límbico/anatomía & histología , Bulbo Raquídeo/anatomía & histología , Mesencéfalo/anatomía & histología , Puente/anatomía & histología , Ratas Endogámicas/anatomía & histología , Médula Espinal/anatomía & histología , Tálamo/anatomía & histologíaRESUMEN
Atrial natriuretic peptide is a potent dilator of aorta and renal and cerebral arteries and inhibits sympathetic tone in the heart in several mammalian species. We examined the possibility that a molecule related to porcine brain natriuretic peptide (pBNP), which acts at the same receptor sites as atrial natriuretic peptide, might provide an alternative source of natriuretic peptide to the cardiovascular system in the rat. An antiserum against pBNP demonstrated profuse immunoreactive innervation of the heart, cerebrovascular tree, and renal arteries. pBNP-like immunoreactive fibers ran in bundles along the surface of the heart, innervating the atria most heavily and penetrating the ventricular myocardium along the coronary arteries. There was greater density of innervation of the right side of the heart compared with the left, particularly in the ventricles, suggesting a parasympathetic origin. The entire cerebrovascular tree was innervated by immunoreactive pBNP fibers, with the densest concentration of immunoreactive fibers along the surface of the internal carotid, middle cerebral, posterior communicating, and anterior cerebral arteries. The proximal renal arteries were not innervated, but as they approached the kidney, they were invested by bundles of immunoreactive pBNP fibers. These axons followed the major branches of the renal artery into the kidney parenchyma, running along the surface of the arterioles up to their entrance into the renal glomeruli. No immunoreactive innervation of the aorta or proximal brachiocephalic, subclavian, or carotid arteries was seen. A substance related to pBNP may serve as a neuromodulator regulating cardiac output as well as blood flow in certain vascular beds.
Asunto(s)
Sistema Cardiovascular/inervación , Arterias Cerebrales/inervación , Proteínas del Tejido Nervioso/análisis , Animales , Axones , Gasto Cardíaco , Atrios Cardíacos/inervación , Ventrículos Cardíacos/inervación , Inmunohistoquímica , Péptido Natriurético Encefálico , Neurotransmisores/fisiología , Ratas , Ratas Endogámicas , Arteria Renal/inervaciónRESUMEN
Brain natriuretic peptide is a recently discovered neuropeptide. We used an antiserum against porcine brain natriuretic peptide to identify a system of immunoreactive innervation of the cerebrovascular tree in the rat. The internal carotid artery and the proximal portions of the middle and anterior cerebral and posterior communicating arteries were the most intensely innervated by immunoreactive fibers. The density of innervation decreased distally along the anterior, middle, and posterior cerebral arteries and the basilar and vertebral arteries. Brain natriuretic peptide and the related atrial natriuretic peptide are known to cause dilatation of cerebral arteries. Our findings suggest that brain natriuretic peptide may serve as a vasodilatory neuromodulator in the cerebral circulation.
Asunto(s)
Química Encefálica , Arterias Cerebrales/inervación , Proteínas del Tejido Nervioso/análisis , Neuronas/química , Animales , Anticuerpos , Encéfalo/irrigación sanguínea , Arterias Cerebrales/metabolismo , Péptido Natriurético Encefálico , Ratas , Ratas EndogámicasRESUMEN
In a previous study (Herbert et al., J. Comp. Neurol. [1990];293:540-580), we demonstrated that the ascending afferent projections from the medulla to the parabrachial nucleus (PB) mark out functionally specific terminal domains within the PB. In this study, we examine the organization of the forebrain afferents to the PB. The PB was found to receive afferents from the infralimbic, the lateral prefrontal, and the insular cortical areas; the dorsomedial, the ventromedial, the median preoptic, and the paraventricular hypothalamic nuclei; the dorsal, the retrochiasmatic, and the lateral hypothalamic areas; the central nucleus of the amygdala; the substantia innominata; and the bed nucleus of the stria terminalis. In general, forebrain areas tend to innervate the same PB subnuclei from which they receive their input. Three major patterns of afferent termination were noted in the PB; these corresponded to the three primary sources of forebrain input to the PB: the cerebral cortex, the hypothalamus, and the basal forebrain. Hypothalamic afferents innervate predominantly rostral portions of the PB, particularly the central lateral and dorsal lateral subnuclei. The basal forebrain projection to the PB ends densely in the external lateral and waist subnuclei. Cortical afferents terminate most heavily in the caudal half of the PB, particularly in the ventral lateral and medial subnuclei. In addition, considerable topography organization was found within the individual projections. For example, tuberal lateral hypothalamic neurons project heavily to the central lateral subnucleus and lightly to the waist area; in contrast, caudal lateral hypothalamic neurons send a moderately heavy projection to both the central lateral and waist subnuclei. Our results show that the forebrain afferents of the PB are topographically organized. These topographical differences may provide a substrate for the diversity of visceral functions associated with the PB.
Asunto(s)
Lóbulo Frontal/citología , Hipotálamo/citología , Puente/citología , Animales , Peroxidasa de Rábano Silvestre , Masculino , Vías Nerviosas/anatomía & histología , Fitohemaglutininas , Ratas , Aglutinina del Germen de Trigo-Peroxidasa de Rábano Silvestre Conjugada , Aglutininas del Germen de TrigoRESUMEN
Brain natriuretic peptide (BNP) is a recently discovered neuropeptide, isolated from the porcine brain, that is highly homologous to atriopeptin (AP), the atrial natriuretic peptide. We used a set of highly selective antisera against the two peptides to map their differential distribution immunohistochemically in the rat central nervous system. BNP immunoreactivity has a distinct distribution, involving many central autonomic and endocrine control structures that contain little if any AP immunoreactivity. AP and BNP belong to a family of neuropeptides that may be important in central cardiovascular control.