Neurochemistry, connectivity and plasticity of small intensely fluorescent (SIF) cells in the rat superior cervical ganglion.
Applying double-labelling immunofluorescence, the peptide content of solitary and clustered small intensely fluorescent (SIF) cells, identified by an antiserum to a selective membrane glycoprotein marker, synaptophysin, was correlated with the presence of catecholamines in the rat superior cervical ganglion. Most of synaptophysin-immunoreactive solitary and clustered SIF cells apparently contained dopamine (indicated by tyrosine hydroxylase-TH) but not noradrenaline (indicated by dopamine-beta-hydroxylase-DBH). Frequently, immunoreactivities for substance P or rarely, neuropeptide Y were colocalized in TH-immunolabeled cells of both types. Immunostaining for vasoactive intestinal polypeptide was found only in solitary SIF cells and was visible in TH-immunoreactive, as well as in TH-nonreactive cells. Very few solitary SIF cells were TH- and DBH-immunoreactive. Solitary and clustered SIF cells, as a rule, were encircled by leu-enkephalin-positive fibres which were also met-enkephalin-arg6-phe7-immunoreactive, indicating proenkephalin as precursor. SIF cells were additionally approached by varicose fibres which contained immunoreactivity for calcitonin gene-related peptide (CGRP) but not for enkephalins. As observed by immuno-electronmicroscopy, fibres that were immunostained for leu-enkephalin or CGRP, deeply invaginated into SIF cell somata. In addition to close membrane appositions, CGRP-immunolabeled fibres exhibited efferent synaptic contacts wih elements of SIF cell clusters. SIF cells were non-reactive to enkephalin-antisera in control ganglia and after transection of the postganglionic nerves (axotomy); but both types exhibited leu-enkephalin in preganglionically transected ganglia (decentralization) in which enkephalin-immunoreactive fibre baskets were absent. Synthesis of enkephalin in SIF cells after decentralization was confirmed by in situ hybridization demonstrating intracytoplasmic proenkephalin messenger-RNA. The findings are indicative for a differential neurochemical equipment of SIF cells in the rat superior cervical ganglion, which mainly is independent to a topographical classification. Moreover, they demonstrate the involvement of two neuropeptides in preganglionic SIF cell innervation. Finally, the observations indicate the capacity of SIF cells for proenkephalin-expression in response to preganglionic denervation.
Heym
C
C
Institut für Anatomie und Zellbiologie, Ruprecht Karls Universität, Heidelberg, Germany.
Common
B
B
Yin
S
S
Klimaschewski
L
L
Couraud
J Y
JY
Bachmann
S
S
D000818:Animals; D004298:Dopamine / Q000032:analysis; D004299:Dopamine beta-Hydroxylase / Q000032:analysis; D004745:Enkephalins / Q000032:analysis; D005260:Female; D005455:Fluorescent Antibody Technique; D005728:Ganglia, Sympathetic / Q000166:cytology* / Q000502:physiology*; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology* / Q000502:physiology*; D009478:Neuropeptide Y / Q000032:analysis; D009638:Norepinephrine / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000032:analysis; D016708:Synaptophysin / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D004745:Enkephalins; D009478:Neuropeptide Y; D016708:Synaptophysin; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D004298:Dopamine; D009638:Norepinephrine