Cocaine- and Amphetamine-Regulated Transcript Peptide Attenuates Phenylephrine-Induced Bradycardia in Anesthetized Rats
Document Type
Article
Publication Date
1-1-2003
Description
The present study was undertaken to investigate the origin of cocaine- and amphetamine-regulated transcript (CART) peptide immunoreactive (irCART) fibers observed in the nucleus of the solitary tract (NTS) and assess the role of CART peptide on phenylephrine (PE)-induced baroreflex. Immunohistochemical and retrograde tract-tracing studies showed that some of the irCART fibers observed in the NTS may have their cell bodies in the nodose ganglia. In urethane-anesthetized rats, intracisternal or bilateral intra-NTS microinjection of the CART peptide fragment 55-102 (0.1-3 nmol), referred to herein as CARTp, consistently and dose dependently attenuated PE-induced bradycardia. CARTp, in the doses used here, caused no significant changes of resting blood pressure or heart rate. Bilateral intra-NTS injections of CART antibody (1:500) potentiated PE-induced bradycardia. Injections of saline, normal rabbit serum, or concomitant injection of CARTp and CART antiserum into the NTS caused no significant changes of PE-induced baroreflex. The result suggests that endogenously released CARTp from primary afferents or exogenously administered CARTp modulates PE-induced baroreflex.
Citation Information
Scruggs, Phouangmala; Dun, Siok L.; and Dun, Nae J.. 2003. Cocaine- and Amphetamine-Regulated Transcript Peptide Attenuates Phenylephrine-Induced Bradycardia in Anesthetized Rats. American Journal of Physiology - Regulatory Integrative and Comparative Physiology. Vol.285(6 54-6). https://doi.org/10.1152/ajpregu.00183.2003 PMID: 12933358 ISSN: 0363-6119