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M M Dietl

Publications and source records attributed to M M Dietl.

At least 19 recordsLinked to original sources
PubMed1991

Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: an autoradiographic and immunohistochemical study.

The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves. The correlation between the distribution of VIP binding sites and immunoreactive fibers and terminals was assessed in a restricted number of regions. A qualitatively good matching was found in the area corticoidea dorsolateralis, hyperstriatum dorsale, hyperstriatum accessorium, nucleus septi lateralis, nuclei dorsomedialis and dorsolateralis thalami, and in some hypothalamic areas. A striking mismatch occurred in the hyperstriatum ventrale, neostriatum, tectum opticum (high to moderate density of binding sites but only few immunoreactive profiles), and in the tuberculum olfactorium, median eminence, and spinal cord (lower density of binding sites but abundant immunoreactive profiles). The paleostriatum, lobus parolfactorius, and ectostriatum were virtually devoid of both binding sites and immunoreactive profiles. The results are discussed in relation to the known actions of VIP in the rodent and avian brain and are compared with previous observations on the distribution of VIP binding sites in the central nervous system of other vertebrates.

Animals↗
PubMed1991

Phylogeny of tachykinin receptor localization in the vertebrate central nervous system: apparent absence of neurokinin-2 and neurokinin-3 binding sites in the human brain.

Binding of [125I]Bolton-Hunter labeled tachykinins substance P (BHSP), neurokinin A (BHNKA) and eledoisin (BHELE) to brain sections from several vertebrates was investigated by receptor autoradiography. Densities of BHSP binding sites were low in fish brain, increased in lower vertebrates, were high in birds and rodents, and relatively constant in cat, monkey and human. In contrast, BHELE binding site densities were moderate in fish brain and high in frog, snake, chick, pigeon, mouse and rat brain. Low and very low densities were localized in guinea pig and cat, while no significant BHELE specific binding was found in monkey and human brain. BHSP and BHELE binding sites were distinctly distributed in the vertebrate brains analyzed. Each ligand showed a characteristic regional distribution which was similar from species to species. The affinity profiles of tachykinins for BHSP and BHELE binding sites as analyzed on frog, chick and rat brain sections, corresponded to the NK1 and NK3 receptor types, respectively. No BHNKA binding sites could be detected in any vertebrate brain investigated. In conclusion, marked species variations exist in the density and distribution of tachykinin receptor types in the vertebrate brain. Thus, neurokinin A receptors (NK2 type) seem to be absent in the vertebrate central nervous system and, while substance P receptors (NK1 type) appear to be preserved and increase in density during evolution, the contrary seems to happen for the eledoisin receptors (NK3 type) which are more abundant in lower vertebrates and apparently absent in primate, particularly human brain.

Animals↗
PubMed1990

Autoradiographic analysis of the distribution of vasoactive intestinal peptide binding sites in the vertebrate central nervous system: a phylogenetic study.

The distribution of vasoactive intestinal peptide (VIP) binding sites in the brain of several vertebrate species was examined by in vitro autoradiography on slide-mounted sections. This study included fish, frog, snake, pigeon, rat, mouse, guinea pig, cat and monkey brain. A fully characterized, monoiodinated form of vasoactive intestinal peptide (M-125I-VIP), which maintains the biological activity of the native peptide in the central nervous system (CNS), was used throughout the study. Among the lower vertebrate species, no significant specific binding was found in the fish brain, whereas in the frog and snake brain, specific VIP binding sites were observed, mainly in the telencephalon. In the pigeon brain, high densities of VIP binding sites were localized in the hyperstriatum, neostriatum, archistriatum, hippocampal area, dorsolateral cortical area and in the optic tectum. Ectostriatum and paleostriatum augmentatum displayed lower densities of specific binding. In mammals, the highest concentrations of VIP binding sites were observed in the rodent brain. In the rat, mouse and guinea pig brain, high densities were detected in the olfactory bulb, external layers of the cerebral cortex, dentate gyrus, midline thalamic nuclei, geniculate nuclei, some hypothalamic nuclei, superior colliculus and locus coeruleus. Intermediate densities were found in amygdala, caudate-putamen, septum and nucleus accumbens, CA1-CA3 fields of the hippocampus and central gray. The cerebellum of these species presented high densities of VIP binding sites, with species to species differences in their localization. The non-specific binding was, however, increased in the rodent cerebellum. Lower densities of VIP binding sites were observed in the cat and monkey CNS. In these two species, the non-specific binding was considerably higher than in the lower mammals brain. In the cat and monkey brain, as in the lower mammals, the highest densities were revealed in the neocortex, dentate gyrus, thalamic nuclei and some midbrain structures including substantia nigra and locus coeruleus. In all the species studied, the white matter was never labeled with M-125I-VIP. This study suggests that VIP binding sites appear relatively early in the evolution of the vertebrate CNS. The most important densities of specific VIP binding sites are observed in the pigeon and rodent brain, whereas the cat and monkey present a marked increase in non-specific binding. It is interesting to note that the distribution of VIP binding sites as revealed by autoradiography is quite conservative in terms of evolution and indicates an association, although non-exclusive, of VIP receptors with brain regions involved in the processing of specific sensory inputs.

Animals↗
PubMed1990

Identification and characterization of somatostatin receptors in neonatal rat long bones.

Somatostatin (somatotropin release inhibiting factor; SRIF) has widespread functions as a modulator of neural activity as well as of endocrine and exocrine secretion. In the present paper, the binding characteristics of somatostatin receptors have been investigated in rat long bones using the stable analogue, 125I-SDZ 204-090, as a ligand. Binding studies revealed the presence of a single class of high-affinity binding sites for 125I-SDZ 204-090 on cells prepared from neonatal rat long bones with an equilibrium dissociation constant (KD) of 70.1 +/- 8.2 pM (n = 3). An excellent correlation was found between the ability of various somatostatin analogues to inhibit growth hormone in pituitary cells and to displace the binding of 125I-SDZ 204-090 to the bone cell preparation, indicating that the receptors are very similar, if not identical. The localization of the somatostatin-binding sites was examined by autoradiography after labelling in vitro and in vivo. The binding sites were shown by both procedures to be selectively localized to the metaphysis of rat long bones. The labelling experiments in vivo indicate that these receptors can be reached in the living animal by circulating somatostatin analogues. In addition, the analogue SMS 201-995 inhibited the forskolin-stimulated adenylate cyclase activity in bone cell suspensions. These results suggest that somatostatin could be an important regulatory factor in bone metabolism.

Adenylyl Cyclases↗
PubMed1989

Substance P receptors in the human spinal cord: decrease in amyotrophic lateral sclerosis.

The distribution of substance P receptors was examined by autoradiography at all levels of the human postmortem spinal cord using the ligand [125I]Bolton-Hunter substance P. Adjacent sections were used to localize substance P-like immunoreactivity by a radioimmunohistochemical technique. In the control spinal cord substance P-like immunoreactivity was found to be highly concentrated in the superficial layers of the dorsal horn, intermediolateral cell columns and lamina X, while lower levels of immunoreactivity were observed in other areas of the grey matter of the spinal cord. In contrast, high densities of substance P binding sites were localized not only to the substantia gelatinosa of the dorsal horn but also to other regions of the grey matter of the spinal cord, particularly in the area of the preganglionic sympathetic neurons in the intermediolateral cell column and in the region of the somatic motor neurons of the ventral horn. In 5 cases of amyotrophic lateral sclerosis we found a marked reduction of substance P binding, especially in the ventral horn associated with the loss of motor neurons. These results suggest a postsynaptic localization of substance P receptors to the motor neurons of the ventral horn in the human spinal cord and a role for substance P in the function of motor neurons.

Adult↗
PubMed1989

5.HT1 receptors in the vertebrate brain. Regional distribution examined by autoradiography.

The regional distribution of high affinity [3H]5-HT recognition sites in the brain of several vertebrates (pigeon, rat, mouse, guinea-pig, cat, dog, monkey and human) was analyzed using in vitro autoradiography. The presence of subtypes of 5-HT1 binding sites was investigated by selective displacements with 8-OH-DPAT, mesulergine and (+/-)SDZ 21-009 at appropriate concentrations to block 5-HT1A, 5-HT1C and 5-HT1B sites respectively. In addition, 5-HT1A and 5-HT1C sites were directly visualized with the more selective radioligands [3H]8-OH-DPAT and [3H]mesulergine, respectively. In the pigeon brain, total [3H]5-HT binding sites were enriched in all telencephalic areas. Densely labelled regions were also present in the optic tectum and the brainstem. No binding was observed in the cerebellum. 8-OH-DPAT and mesulergine only displaced a small proportion of [3H]5-HT binding in most of the areas where high concentrations of 5-HT1 sites were found. (+/-)SDZ 21-009 did not affect [3H]5-HT binding in the regions examined. Taking into account our pharmacological studies, these results suggest that the majority of 5-HT1 sites belong to the 5-HT1D subtype in the pigeon brain. In the mammalian species investigated high levels of [3H]5-HT binding were found in the neo-cortex, hippocampal formation, basal ganglia and related structures (substantia nigra), raphe dorsalis, nucleus superior colliculus and choroid plexus. However, these brain areas were differentially enriched in subtypes of 5-HT1 recognition sites.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1989

Substance P-induced reduction in the initial accumulation of cytosolic myo-[3H]inositol in rat parotid acinar cells mediated by the NK1 tachykinin receptor.

Stimulation of rat parotid acinar cells by the tachykinin neurokinin (NK) 1 receptor agonist substance P (SP) resulted in a significant reduction in the initial accumulation of cytosolic myo-[3H]inositol. This effect was rapid, because a reduction of approximately 15% could be seen already at 30 s. with the maximal effect (approximately 45%) being observed at 15 min. The response to SP stimulation was temperature dependent, because at 4 degrees C no reduction was found. In addition, at 4 degrees C, cytosolic myo-[3H]inositol represented only 10% of the labeled inositol accumulated at 37 degrees C. The SP-induced reduction in cytosolic myo-[3H]inositol accumulation was concentration dependent; the EC50 obtained for SP was 5.8 +/- 2.5 nM. Spantide [D-Arg1, D-Trp7.9, Leu11]SP), a SP antagonist, used at a concentration of 10(-5) M, gave a competitive shift of the dose-response curve to SP. Various tachykinins and their analogs were evaluated for their ability to reduce cytosolic myo-[3H]inositol. [L-Pro9]SP and SP methyl ester, two highly selective agonists of NK1 receptors, reduced the initial accumulation of myo-[3H]inositol with EC50 values of 2.3 and 67.0 nM, respectively. Long SP C-terminal fragments were more potent than shorter ones. SP N-terminal fragments and SP free acid were without effect. [Pro7]NKB, a selective NKB analog, had no effect. The rank order of potency of mammalian tachykinins was SP greater than NKA greater than NKB. These findings and the close correlation between EC50 values and IC50 values obtained in binding studies implicate the NK1 receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Visualization of a novel serotonin recognition site (5-HT1D) in the human brain by autoradiography.

The localization of a novel serotonin (5-hydroxytryptamine, 5-HT) recognition site named 5-HT1D was studied by autoradiography in human postmortem brain material. Serotonin-1 sites were labeled with [3H]5-HT. The different subpopulations of 5-HT1 sites were investigated by the use of unlabeled selective compounds. 8-OH-DPAT (8-hydroxy-2-[N,N-di-n-propyl-amino]tetralin) was used to block [3H]5-HT binding to 5-HT1A, the beta-blocker (-)-21 009 (4-[3-ter-butyl-amino-2-hydroxy-propoxy]indol-2-carbonic acid isopropyl ester) to 5-HT1B and the ergoline mesulergine to 5-HT1C recognition sites. 5-HT1D sites were defined as the binding sites remaining when both 8-OH-DPAT and mesulergine were added to the incubation medium. Under these conditions, 5-HT1D sites represented a high proportion of total [3H]5-HT binding sites in the basal ganglia and substantia nigra. Lower proportions were observed in other brain areas such as the hippocampal formation and raphé nuclei. 5-HT1D sites thus represent the majority of 5-HT1 binding sites in the striatonigral pathway in man. This localization suggests an involvement of these sites in the mediation of serotoninergic mechanisms in basal ganglia functions and a possible role in brain diseases where these areas are known to be involved.

Autoradiography↗
PubMed1988

Neurotransmitter receptors in the avian brain. I. Dopamine receptors.

The distribution of dopamine D1 and D2 receptors was investigated in the pigeon brain using in vitro receptor autoradiography. D1 receptors were labeled in slide-mounted tissue sections with [3H]SCH 23390. The agonist [3H]CV 205-502 and the antagonist [3H]spiroperidol were used to label D2 receptors. The highest densities of both D1 and D2 receptors were concentrated in the paleostriatum augmentatum, lobus paraolfactorius and olfactory tubercle. D1 receptors were in addition enriched in the entire pigeon telencephalon with exception of the ectostriatum. In contrast, no significant densities of D2 receptors were observed in the pallium. D2 but not D1 receptors were present in the tectum and nucleus pretectalis. The cerebellum presented D1 but not D2 receptors. These results demonstrate that in the avian brain, like in the mammalian one, both dopamine D1 and D2 receptors are concentrated in 'striatal' areas, while the telencephalon is rich in D1 but not D2 receptors.

Animals↗
PubMed1988

Neurotransmitter receptors in the avian brain. II. Muscarinic cholinergic receptors.

The characteristics and distribution of muscarinic cholinergic receptors were examined in the pigeon brain using in vitro receptor autoradiography. The antagonist N-[3H]methylscopolamine was used as ligand and the presence of the putative subtypes M1 and M2 of the muscarinic cholinergic receptors examined using carbachol and pirenzepine as displacers. The highest densities of muscarinic cholinergic receptors in the pigeon brain were localized in the paleostriatum augmentatum and the lobus parolfactorius, areas homologous to the mammalian corpus striatum. In contrast, the paleostriatum primitivum, corresponding to the mammalian globus pallidus, was poor in muscarinic cholinergic receptors. The rest of the telencephalon was also rich in muscarinic cholinergic receptors, while thalamic, hypothalamic and brainstem areas, as well as the tectum, presented intermediate densities, similar to the mammalian brain. Exceptions to that were the hippocampus, which was poorly labeled in the bird brain and the cerebellum, which presented intermediate to high densities of muscarinic cholinergic receptors in the bird brain. Preliminary pharmacological studies suggest differences between avian and mammalian receptor subtypes, since carbachol and pirenzepine apparently did not recognize two different receptor subpopulations.

Animals↗
PubMed1988

Neurotransmitter receptors in the avian brain. III. GABA-benzodiazepine receptors.

GABA/benzodiazepine (BZ) receptors were localized in the pigeon brain by in vitro receptor autoradiography using [3]flunitrazepam as ligand. Highest densities of binding sites were observed in the optic tectum, in the nucleus pretectalis, the nucleus intercollicularis and the substantia gelatinosa of the spinal cord. Intermediate densities were found in the forebrain, particularly the paleostriatum primitivum, the nucleus rotundus and the cerebellum. Low densities were detected in the midbrain and brainstem. The paleostriatum primitivum and cerebellum were enriched in receptors of the BZ type I, as indicated by their high affinity for compound CL 218872. The addition of GABA resulted in an enhanced binding of the ligand in all brain regions. All these results indicate that GABA/BZ receptors in the pigeon brain present similar pharmacological properties and comparable anatomical distribution to those in mammalian brain.

Animals↗
PubMed1988

The ontogeny of brain neurotensin receptors studied by autoradiography.

Using in vitro receptor autoradiographic techniques we have analysed the pre- and postnatal development of neurotensin receptors in the rat brain. Receptors were labeled with [3H] or [125I]neurotensin in mounted tissue sections from animals of ages gestational day 14 until the postnatal day 21 as well as young adult animals. Very low densities of neurotensin receptors were visualized on gestational days 14 and 15. Between gestational days 16 and 18 a marked increase in the density of neurotensin receptors was seen in the developing neocortex. Densities in other brain areas, particularly the midbrain and brainstem were much lower than cortical densities. The density of neurotensin receptors in the cortex increased through the last part of the gestation and early postnatal life until it peaked at the end of the first postnatal week. After that, neurotensin receptor binding decreased dramatically reaching lower densities seen in the adult animal at the end of the third postnatal week. Development of neurotensin receptors in other brain areas followed very different time patterns. Neurotensin receptors in the midbrain were seen first at gestational day 18 and increased slowly with development to reach adult levels at about the second week of postnatal life. Neurotensin receptors in the hippocampal formation demonstrated postnatal development; they were detected at postnatal day 5 and showed a developmental peak around the second week. These patterns were seen with both 3H- and 125I-labeled neurotensin, thus excluding possible differential quenching artifacts. These clear differential regional ontogenetic patterns for neurotensin receptors are the main findings of these experiments. The very high densities present in the cortex even in fetal stages suggest that neurotensin could play a role in the development of the brain.

Animals↗
PubMed1988

Quantitative autoradiographic mapping of neurohypophysial hormone binding sites in the rat forebrain and pituitary gland--I. Characterization of different types of binding sites and their distribution in the Long-Evans strain.

Oxytocin and vasopressin binding sites were localized and characterized by quantitative autoradiography on consecutive sections of Long-Evans rat forebrains and pituitary glands, incubated in the presence of 5 nM [3H]oxytocin or 5 nM [3H]vasopressin. In the forebrain, two types of neurohypophysial hormone binding sites were thus defined. (1) Oxytocin/vasopressin sites with similar nanomolar-range affinities for [3H]oxytocin and [3H]vasopressin; both tritiated peptides were displaced from these sites in the presence of 10 microM of either oxytocin or vasopressin. The main areas bearing such sites were the ventral subiculum, several nuclei of the amygdala, the ventromedial hypothalamic nucleus, the bed nucleus of the stria terminalis and the olfactory tubercle. (2) Selective vasopressin sites, binding [3H]vasopressin with nanomolar-range affinity and [3H]oxytocin with a much lower affinity; these sites were not labelled in the presence of 5 nM [3H]oxytocin, and 10 microM oxytocin displaced [3H]vasopressin binding by 80%. Such sites occurred in several thalamic nuclei, in the dopaminergic A13 cell group of the zona incerta, the suprachiasmatic nucleus, the fundus striati and the lateral septal nucleus. No selective oxytocin sites were detected. Different oxytocin and vasopressin binding characteristics were found in the hypothalamo-neurohypophysial system. In the paraventricular and supraoptic nuclei and in the pituitary neural lobe the [3H]vasopressin binding density was twice that of [3H]oxytocin; vasopressin was always more potent than oxytocin in displacing both [3H]vasopressin and [3H]oxytocin binding from those sites. Interaction of the tritiated peptides with neurophysins cannot be completely ruled out in these locations. The present data are discussed in correlation with the functional roles of the neurohypophysial peptides in the brain and the pharmacological characteristics of their receptors.

Animals↗
PubMed1988

Quantitative autoradiographic mapping of neurohypophysial hormone binding sites in the rat forebrain and pituitary gland--II. Comparative study on the Long-Evans and Brattleboro strains.

The anatomical distribution and pharmacological characteristics of the different types of neurohypophysial hormone binding sites were compared in the forebrains and pituitary glands of Long-Evans rats and its mutant Brattleboro strain, genetically deficient in vasopressin. Quantitative autoradiography on sections incubated in the presence of 5 nM of either [3H]oxytocin or [3H]vasopressin revealed the presence of the same types of sites in the brains of both strains but noticeable variations in their densities were found in several areas. In the forebrain, oxytocin/vasopressin sites, which bind both peptides with similar high nanomolar affinities, had the same locations and densities in the ventral subiculum, in several nuclei of the amygdala, the bed nucleus of the stria terminalis and the olfactory tubercle. The density of such sites was, in contrast, lower in the ventromedial hypothalamic nucleus of the Brattleboro rat. Selective vasopressin sites which bind [3H]vasopressin with a nanomolar-range affinity and [3H]oxytocin with a much lower affinity showed more variations. They were not found in the Brattleboro rat thalamus but were highly concentrated in several thalamic nuclei in the Long-Evans rat. Conversely, their densities were higher in the dopaminergic A13 cell group of the zona incerta and the suprachiasmatic nucleus of the Brattleboro rat. Their densities were similar in the lateral septal nucleus and in the fundus striati of both strains. In the hypothalamo-neurohypophysial system, [3H]oxytocin and [3H]vasopressin binding occurred in the Long-Evans rat with characteristics different from those found in other brain areas. In the Brattleboro rat, no [3H]vasopressin binding and only low [3H]oxytocin binding, restricted to the magnocellular nuclei, were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Regulatory peptide receptors: visualization by autoradiography.

The receptors for regulatory peptides have been extensively characterized using radioligand binding techniques. By combining these binding techniques with autoradiography it is possible to visualize at the light and electron microscopic levels the anatomical and cellular localization of these receptors. In this review we discuss the procedures used to label peptide receptors for autoradiography and the peculiarities of peptides as ligands. The utilization of autoradiography in mapping peptide receptors in brain and peripheral tissues, some of the new insights revealed by these studies particularly the problem of 'mismatch' between endogenous peptides and receptors, the existence of multiple receptors for a given peptide family and the use of peptide receptor autoradiography in human tissues are also reviewed.

Animals↗
PubMed1987

On the distribution of cholecystokinin receptor binding sites in the human brain: an autoradiographic study.

Cholecystokinin (CCK) binding sites were localized by in vitro autoradiography in human postmortem brain materials from 12 patients without reported neurological diseases using [125I]Bolton-Hunter CCK octapeptide (BHCCK-8) as a ligand. The pharmacological characteristics of BHCCK-8 binding to mounted tissue sections were comparable to those previously reported in the rat. CCK-8 being the most potent displacer, followed by caerulein, CCK-4, and gastrin I. The distribution of BHCCK-8 binding sites was heterogeneous. These sites were highly concentrated in a limited number of gray matter areas and nuclei. The highest binding densities were seen in the glomerular and external plexiform layers of the olfactory bulb. BHCCK-8 binding sites were also enriched in the neocortex, where they presented a laminar distribution with low levels in lamina I, moderate concentration in laminae II to IV, high density in lamina V, and low levels in lamina VI. A different laminar distribution was seen in the visual cortex, where a low receptor density was observed in lamina IV but higher density in laminae II and VI. In the basal ganglia the nucleus accumbens, caudatus, and the putamen presented moderate to high densities of binding sites, while the globus pallidus lacked sites of BHCCK-8 binding. In the limbic system the only area presenting moderate to high density was the amygdaloid complex, particularly in the granular nucleus, while most of the thalamic nuclei were extremely poor or lacked BHCCK-8 binding. The hippocampal formation showed low (CA1-3) to moderate (subiculum) densities. Midbrain areas generally disclosed very low levels of BHCCK-8 binding sites. The pontine gray and the nucleus reticularis tegmenti pontis showed a relatively high density of CCK-8 receptor specific binding. Moderate to very high densities were found in few nuclei of the lower brainstem and spinal cord as the inferior olives and their accessory nuclei, the arcuate nuclei, the striae medullares, the efferent (motor) nucleus of the vagus, and the substantia gelatinosa of the cervical and thoracic spinal cord. These results are discussed in relation to the distribution of endogenous peptide and to the known physiological and pharmacological effects of substances acting on these receptors.

Aged↗