Neurotensin receptors in the human amygdaloid complex. Topographical and quantitative autoradiographic study.

The distribution of high affinity 125I-neurotensin (NT) binding sites were investigated in the amygdaloid complex of adult humans by means of dry film and emulsion autoradiography. Autoradiograms were analysed quantitatively using [125I] standards and an image analyser system, and data obtained were converted to nCi of ligand bound per mg tissue. High densities of 125I-NT binding sites were found in the following amygdaloid structures the dorsal part of the accessory basal nucleus, the medial part of the cortical nucleus, the lateral subdivision of the central nucleus, the paralaminar nucleus, the amygdalohippocampal transition area and the rostral portions of the anterior amygdaloid area. The ventral part of the accessory basal nucleus, the intercalated cell groups and the remaining parts of the anterior amygdaloid area showed moderate density of NT binding sites, while the medial, basal and lateral amygdaloid nuclei, the lateral part of the cortical nucleus, the medial subdivision of the central nucleus, as well as the corticoamygdaloid transition area exhibited low densities of 125I-NT binding sites. At microscopic level, silver grains appeared more or less evenly distributed over both neuronal perikarya and the surrounding neuropil. In comparison to NT-immunoreactivity, NT receptors showed mismatching distribution throughout most parts of the amygdala, with the exception of the lateral subdivision of the central nucleus, where NT-immunoreactive perikarya and nerve fibers as well as 125I-NT binding sites were found in high density.

Immunohistochemical localization of calcitonin gene-related peptide in the terete nucleus of the rat hypothalamus.

The topographical distribution of calcitonin gene-related peptide (CGRP) containing neuronal elements in the posterior hypothalamus has been re-examined by means of indirect labeled immunohistochemistry in the rat. In contrast to previous findings, no CGRP-like immunoreactive neuronal perikarya were present in the premamillary nuclei, but they form a small group of cells, which is identical to the recently described terete nucleus. In coronal sections, this small and rounded cluster of intermingled CGRP-immunopositive perikarya and fibers is situated in the lateral hypothalamus at the premamillary level, ventrolateral to the fornix. Perikarya, dendrites, presynaptic terminals, as well as nonmyelinated and some myelinated axons were labeled by CGRP-like immunoreactive material within and in the immediate vicinity of the terete nucleus. On some of the CGRP-positive neurons, neuropeptide Y-immunoreactive axon terminals establish synaptic contacts.

Immunohistochemical mapping of neuropeptides in the premamillary region of the hypothalamus in rats.

The topographical distribution of neuropeptide-containing cell bodies, fibers and terminals was studied in the premamillary region of the rat hypothalamus using light microscopic immunohistochemistry. Alternate coronal sections through the posterior third of the hypothalamus of normal and colchicine-treated male rats were immunostained for 19 different neuropeptides and their distributions were mapped throughout the following structures: the ventral and dorsal premamillary, the supramamillary, the tuberomamillary and the posterior hypothalamic nuclei, as well as the premamillary portion of the arcuate nucleus and the postinfundibular median eminence. Seventeen of the investigated neuropeptides were present in neuronal perikarya, nerve fibers and terminals while the gonadotropin associated peptide and vasopressin occurred only in fibers and terminals. Growth hormone-releasing hormone-, somatostatin-, alpha-melanocyte stimulating hormone-, adrenocorticotropin-, beta-endorphin- and neuropeptide Y-immunoreactive neurons were seen exclusively in the premamillary portion of the arcuate nucleus. Thyrotropin-releasing hormone-, dynorphin A- and galanin-containing neurons were distributed mainly in the arcuate and the tuberomamillary nuclei. A high number of methionine- and leucine-enkephalin-immunoreactive cells were detected in the arcuate and dorsal premamillary nuclei, as well as in the area ventrolateral to the fornix. Substance P-immunoreactive perikarya were present in very high number within the entire region, in particular in the ventral and dorsal premamillary nuclei. Cell bodies labelled with cholecystokinin- and calcitonin gene-related peptide antisera were found predominantly in the supramamillary and the terete nuclei, respectively. Corticotropin-releasing hormone-, vasoactive intestinal polypeptide- and neurotensin-immunoreactive neurons were scattered randomly in low number, mostly in the arcuate and the ventral and dorsal premamillary nuclei. Peptidergic fibers were distributed unevenly throughout the whole region, with each peptide showing an individual distribution pattern. The highest density of immunoreactive fibers was presented in the ventral half of the region including the arcuate, the ventral premamillary and the tuberomamillary nuclei. The supramamillary nucleus showed moderately dense fiber networks, while the dorsal premamillary and the posterior hypothalamic nuclei were poor in peptidergic fibers.