Distribution of calcitonin gene-related peptide-like immunoreactivity in the medulla oblongata of the cat, in relation to choline acetyltransferase-immunoreactive motoneurones and substance P-immunoreactive fibres.
The immunohistochemical distribution of calcitonin gene-related peptide (CGRP)-like immunoreactivity (ir) in the cat medulla oblongata was examined using an antiserum to rat alpha-CGRP. Comparative distributions of substance P (SP)-like and choline acetyltransferase (ChAT)-like ir were also studied on sections adjacent to those stained for CGRP, and on sections simultaneously stained for CGRP by double staining techniques. The vast majority of ChAT-ir motoneurones in somatomotor or branchiomotor cranial nuclei (of VI, VII and XII nerves) and their accessory nuclei also displayed a coarsely granular CGRP-ir, shown by electron microscopic examination to represent immunoreactive Golgi bodies. The nucleus ambiguus (IX and X nerves), a mixed branchiomotor and visceromotor nucleus, showed CGRP-ir in a lower proportion of its motoneurones, whereas the purely viseromotor dorsal motor vagal nucleus (X nerve) contained no CGRP-ir cells. A few CGRP-ir but ChAT-negative cells were seen in the ventromedial reticular formation, lateral cuneate nucleus, infratrigeminal nucleus and nucleus of the solitary tract. Coarse, often varicose CGRP-ir fibres were most prominent in the X and IX cranial nerve rootlets, the spinal tract of the V nerve and the solitary tract, and also in the V spinal nucleus and nucleus of the solitary tract. Many of these also appeared to contain SP-ir. The central patterns of CGRP and SP-ir fibres thus reflect the previously reported coexistence of these peptides in sensory afferent cells of the trigeminal and nodose ganglia. These results are consistent with a role for CGRP as a transmitter or modulator in efferents to striated muscle, sensory afferents and intrinsic neurones in the cat brain stem.
Batten
T F
TF
Department of Cardiovascular Studies, University of Leeds, UK.
Lo
V K
VK
Maqbool
A
A
McWilliam
P N
PN
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D002415:Cats; D002795:Choline O-Acetyltransferase / Q000032:analysis*; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000032:analysis*; D009046:Motor Neurons / Q000032:analysis / Q000201:enzymology; D009412:Nerve Fibers / Q000032:analysis; D009474:Neurons / Q000032:analysis*; D013373:Substance P / Q000032:analysis*
D013373:Substance P; D002795:Choline O-Acetyltransferase; D015740:Calcitonin Gene-Related Peptide