Release of calcitonin gene-related peptide from the jugular-nodose ganglion complex in rats--a new model to examine the role of cardiac peptidergic and nitrergic innervation.
OBJECTIVE
Afferent information from the heart and the lung is conveyed to the brainstem by primary afferent fibers originating from vagal sensory neurons (jugular-nodose ganglion complex, JNC). The present study was made to evaluate if release of the sensory neuropeptide calcitonin gene-related peptide (CGRP) from the JNC can be used as a model for future studies on changes in neuropeptide release under pathological conditions of the heart.


METHODS
Freshly isolated rat JNC's were passed through a series of solutions based on oxygenated synthetic interstitial fluid (SIF). Substances such as the TRPV1 receptor agonist capsaicin and the nitric oxide (NO) donor sodium nitroprusside (SNP) were added as excitatory test stimuli. The eluates were processed using an enzyme immuno-assay (EIA) for measurement of CGRP concentrations. Immunohistochemistry was used to visualize CGRP containing and NO producing neurons in the JNC.


RESULTS
Both SNP and capsaicin caused significant increases in CGRP release. CGRP-immunoreactive neurons (somata) were preferentially found in the jugular ganglion, whereas neurons immunoreactive for neuronal NO synthase were mostly localized in the nodose ganglion.


CONCLUSIONS
The present study demonstrates an easily reproducible model for measuring stimulated CGRP release from vagal afferents arising from the JNC. Nitric oxide produced by vagal afferents may stimulate CGRP release upon afferent activation.
Strecker
Thomas
T
Institute of Physiology and Pathophysiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Universitätsstr. 17, D-91054 Erlangen, Germany. strecker@physiologie1.uni-erlangen.de
Koulchitsky
Stanislav
S
Dieterle
Anne
A
Neuhuber
Winfried L
WL
Weyand
Michael
M
Messlinger
Karl
K
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002211:Capsaicin / Q000378:metabolism; D006321:Heart / Q000294:innervation*; D008297:Male; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D009599:Nitroprusside / Q000378:metabolism; D009620:Nodose Ganglion / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018689:Sensory System Agents / Q000378:metabolism; D014630:Vagus Nerve / Q000166:cytology* / Q000378:metabolism
D020030:Nitric Oxide Donors; D018689:Sensory System Agents; D009599:Nitroprusside; D052248:Nitric Oxide Synthase Type I; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin