S. Girgis

Distribution of calcitonin gene-related peptide in the rat peripheral nervous system with reference to its coexistence with substance P

This immunocytochemical study, using a double-staining method, showed that calcitonin gene-related peptide-like immunoreactive structures are widely distributed in the peripheral nervous system and that many of them coexist with substance P-like immunoreactive structures in single sensory ganglion cells. Neurons positive for calcitonin gene-related peptide but negative for substance P were detected in sensory ganglia. These cells were large (about 30-45 micron in diameter); these primary sensory neurons containing calcitonin gene-related peptide can probably act independently of substance P. There were neurons containing calcitonin gene-related peptide without substance P in the pterygopalatine ganglion, although these cells were less numerous than in the sensory ganglia. In consecutive sections, calcitonin gene-related peptide-like structures occurred in thyroid parafollicular cells, which also contain calcitonin. This suggested that messenger RNA for producing calcitonin gene-related peptide is also present in the thyroid, and like calcitonin, calcitonin gene-related peptide may have a peripheral physiological role.

Coexistence of calcitonin gene-related peptide and substance P-like peptide in single cells of the trigeminal ganglion of the rat: immunohistochemical analysis

The localization of calcitonin gene-related peptide (CGRP) and substance P (SP) in the rat trigeminal ganglion was examined by means of the indirect immunofluorescent method. About 40% of neurons in the ganglion contained CGRP-like immunoreactivity (CGRPI), while about 20% of neurons showed SP-like immunoreactivity (SPI). In serial sections, nearly all the SPI neurons contained CGRPI.

Topographic localization of calcitonin gene-related peptide in the rat brain: An immunohistochemical analysis

Abstract The distribution of immunoreactive calcitonin gene-related peptide in the rat brain was investigated by means of an indirect immunofluorescence method. In addition to previously reported calcitonin gene-related peptide-like immunoreactive structure-containing sites such as the nucleus ambiguus, nucleus originis nervi facialis, nucleus originis nervi hypoglossi, nucleus peripeduncularis and nucleus parabrachialis, the present study demonstrated a far wider distribution of calcitonin gene-related peptide-like immunoreactive structure-containing cells in the rat brain, i.e. the nucleus hypothalamicus lateralis. nucleus ventromedialis thalami, colliculus superior, lemniscus lateralis, gyrus dentatus. nucleus olivaris superior, nucleus tractus solitarii, nucleus cuneiformis, nucleus parabigeminalis and a proportion of the Purkinje cells. We have also demonstrated a more extensive network of calcitonin gene-related peptide-like immunoreactive fibers distributed in various areas throughout the rat brain than has been reported previously such as the colliculus inferior, nucleus olivaris superior, nucleus vestibularis lateralis and inferions, and nucleus cochlearis dorsalis and ventralis, etc.

Immunohistochemical evidence for the coexistence of calcitonin gene-related peptide- and choline acetyltransferase-like immunoreactivity in neurons of the rat hypoglossal, facial and ambiguus nuclei

The present immunocytochemical study demonstrates that calcitonin gene-related peptide-like immunoreactivity (CGRPI) coexists with acetylcholine in single cells of hypoglossal, facial and ambiguus nuclei. The experiments were done using alternate frozen sections from relevant regions of the rat brain. We further show that CGRPI is localized in the nerve terminals that form neuromuscular junctions in the tongue muscles.

Effect of calcitonin gene-related peptide on contraction of striated muscle in the mouse

We have found ultrastructurally calcitonin gene-related peptide-like immunoreactivity in the axon terminal within the synaptic trough of neuromuscular junction of the mouse. We determined, using pharmacological means, with a phrenic nerve-diaphragm preparation, that this peptide enhances muscle contraction during stimulation of the nerve fibers or direct stimulation of the muscle. This effect is probably brought about via the receptor for this peptide not the acetylcholine receptor.

Autoradiographic localization of calcitonin gene-related peptide binding sites in human and rat brains

125I-calcitonin gene-related peptide (CGRP) binding sites were mapped in the human brain and rat brains by in vitro macroautoradiography, and compared to each other. Binding experiments were made to characterize 125I-CGRP binding on the human and rat brains. Scatchard analysis of saturation experiments from slide-mounted sections of the human and rat cerebellum displayed 125I-CGRP binding sites with a dissociation constant (Kd) of 0.17 nM and 0.11 nM, respectively, and a maximal number of binding sites (Bmax) of 96.8 fmol/mg and 23.0 fmol/mg protein. 125I-CGRP binding was time-dependent, reversible and saturable with high affinity in the brains. Autoradiograms showed a discrete distribution of 125I-CGRP binding sites throughout the brains of human and rat with patterns similar to each other. In the human brain, the highest binding was seen in the cerebellum, inferior olivary nuclear complex, certain parts of the central gray matter, arcuate nuclei of the medulla oblongata and dorsal motor nucleus of the vagus, and densities of CGRP-binding sites were high in the nucleus accumbens, amygdala, tail of the nucleus caudatus, substantia nigra, ventral tegmental area, medial portion of the inferior colliculus, medial pontine nuclei, locus coeruleus, inferior vestibular nucleus, substantia gelatinosa of the spinal trigeminal nucleus, nucleus of the solitary tract and nucleus cuneatus lateralis. In the rat, high densities were found in the hippocampus pars anterior, nucleus accumbens, ventral and caudal portions of the nucleus caudatus-putamen, central and basolateral nuclei of the amygdala, caudal portion of the insular cortex, medial geniculate body, superior and inferior colliculi, certain portions of the central gray matter, locus coeruleus, inferior olivary nuclei, vagal complex, nucleus cuneatus lateralis and cerebellum. In contrast, in both species, most of the cortical areas including the hippocampus, most of the thalamus, and hypothalamus exhibited few binding sites. In addition, high quantities of the binding sites were seen on the pia mater and on walls of blood vessels in the brain and subarachnoidea. These results revealed essentially homologous locations of CGRP binding sites in the human and rat central nervous systems and well corresponding distributions of binding sites and endogenous CGRP-like immunoreactivity.

Distribution and origins of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, vasoactive intestinal polypeptide (VIP)- and neuropeptide Y (NPY)-containing nerve fibers in the pineal gland of gerbils

In the pineal gland of gerbils, substance P (SP)-, calcitonin gene-related peptide (CGRP)-, vasoactive intestinal polypeptide (VIP)- and neuropeptide Y (NPY)-containing nerve fibers were demonstrated immunohistochemically. After intrapineal injection of biotin-wheat germ agglutinin, origins of fibers were examined by the combined technique of tracing method and immunohistochemistry. It was confirmed that SP- and CGRP-fibers originated from the trigeminal ganglion, VIP-fibers from the pterygopalatine ganglion and NPY-fibers from the superior cervical ganglion.

Two distinct calcitonin gene-related peptide-containing peripheral nervous systems: Distribution and quantitative differences between the iris and cerebral artery with special reference to substance P

The present study first shows that calcitonin gene-related peptide(CGRP)-like immunoreactive (CGRPI) nerve fibers in the cerebral arteries contained substance P (SP) and originated from small- to medium-sized CGRPI cells exhibiting SP immunoreactivity (SPI) in the trigeminal ganglion. The iris contained CGRPI/SPI-costorage nerve fibers and many CGRPI fibers lacking SPI. These fibers originated from large CGRPI cells lacking SPI in the trigeminal ganglion. The heterogenous subpopulations of CGRPI fibers in the iris suggest that CGRP is involved in a variety of functions in this structure.

Calcitonin gene-related peptidergic projection from the parabrachial area to the forebrain and diencephalon in the rat: An immunohistochemical analysis

We investigated ascending fiber projections of calcitonin gene-related peptide from the parabrachial area to the forebrain and diencephalon in the rat using immunocytochemistry. Destruction of the lateral portion of the dorsal parabrachial area resulted in a marked ipsilateral decrease in the fibers containing calcitonin gene-related peptide in the ventromedial hypothalamic nucleus, indicating that cells containing calcitonin gene-related peptide in the lateral portion of the dorsal parabrachial area projected to the ipsilateral ventromedial hypothalamic nucleus. Destruction of the ventral portion of the parabrachial area resulted in a marked decrease of fibers containing calcitonin gene-related peptide in the bed nucleus of the stria terminalis, the central amygdaloid nucleus and the lateral hypothalamus just medial to the crus cerebri (the far-lateral hypothalamus), and a less marked decrease in the ventromedial thalamic nucleus. This means that there are projections from cells containing calcitonin gene-related peptide in the ventral portion of the parabrachial area to the first three regions just mentioned, and to some extent to the last.

Origins and distribution of calcitonin gene-related peptide-containing nerves in the wall of the cerebral arteries of the guinea pig with special reference to the coexistence with substance P

The origins and overall distribution of calcitonin gene-related peptide-like immunoreactivity (CGRPI) in the wall of the cerebral arteries were investigated in the guinea pig by using whole-mounts. Two types of CGRPI fibers were seen; one forming dense fiber bands, located among the periadventitial nerves, and the other forming a meshwork. CGRPI fibers in the periadventitial nerves often leave these nerves to form a meshwork, of a density that varies according to the diameter or location of the blood vessel. The present study showed that CGRPI fibers in the walls of the carotid arterial system originated from the trigeminal ganglion, and those in the vertebrobasilar arterial system from other origins besides the trigeminal ganglion. We also examined the coexistence of this peptide with substance P-like immunoreactive (SPI) structures in a single neuron system. Double staining immunocytochemistry showed that the patterns of the running of CGRPI and SPI fibers in the wall of the cerebral arteries were similar, and this method also demonstrated the presence of neurons containing both CGRPI and SPI structures in single cells of the trigeminal ganglion, which is the major origin of these fibers in the cerebral arteries.