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Depletion of substance P and glutamate by capsaicin blocks respiratory rhythm in neonatal rat in vitro.

Authors :
Morgado-Valle C
Feldman JL
Source :
The Journal of physiology [J Physiol] 2004 Mar 16; Vol. 555 (Pt 3), pp. 783-92. Date of Electronic Publication: 2004 Jan 14.
Publication Year :
2004

Abstract

The specific role of the neuromodulator substance P (SP) and its target, the neurokinin 1 receptor (NK1R), in the generation and regulation of respiratory activity is not known. The preBötzinger complex (preBötC), an essential site for respiratory rhythm generation, contains glutamatergic NK1R-expressing neurones that are strongly modulated by exogenously applied SP or acute pharmacological blockade of NK1Rs. We investigated the effects of capsaicin, which depletes neuropeptides (including SP) and glutamate from presynaptic terminals, on respiratory motor output in medullary slice preparations of neonatal rat that generate respiratory-related activity. Bath application of capsaicin slowed respiratory motor output in a dose- and time-dependent manner. Respiratory rhythm could be restored by bath application of SP or glutamate transporter blockers. Capsaicin also evoked dose-dependent glutamate release and depleted SP in fibres within the preBötC. Our results suggest that depletion of SP (or other peptides) and/or glutamate by capsaicin causes a cessation of respiratory rhythm in neonatal rat slices.

Details

Language :
English
ISSN :
0022-3751
Volume :
555
Issue :
Pt 3
Database :
MEDLINE
Journal :
The Journal of physiology
Publication Type :
Academic Journal
Accession number :
14724197
Full Text :
https://doi.org/10.1113/jphysiol.2003.060350