Central effects of 5-HT on respiratory and hypoglossal activities in the adult cat.
The activities of the diaphragmatic, internal intercostal and hypoglossal-innervated muscles were studied in adult decerebrate cats in response to 5-HT and related agents (8-OH-DPAT and DOI). The drugs were placed on the floor of the IVth ventricle. The mean respiratory frequency (Fi) increased (124-193% of the control value) within 3 min of the 5-HT application, and decreased thereafter (30-90%). The mean Ti and Te changed similarly, but opposite to Fi. With some delay, the hypoglossal-innervated muscles were tonically activated or exhibited increased activities. Methysergide pretreatment completely blocked the effect of 5-HT on all the respiratory parameters and the hypoglossal-innervated muscles activities. The responses to 8-OH-DPAT and DOI indicate that 5-HT modulates the respiratory frequency via activation of both 5-HT1A and 5-HT2 receptors. Nevertheless, the effect of 5-HT on both the expiratory and hypoglossal-innervated muscles seems to depend on 5-HT2 receptors activation only.
Laboratoire de Neurophysiologie Clinique et Expérimentale, Ontogenèse des Systèmes Moteurs Intégres, URA 1331 CNRS, Amiens, France.
D
D
Rose
J
J
Khater-Boidin
P
P
Toussaint
B
B
Duron
D000818:Animals; D002415:Cats; D003655:Decerebrate State / Q000503:physiopathology; D003964:Diaphragm / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D005260:Female; D007002:Hypoglossal Nerve / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D015656:Respiratory Mechanics / Q000187:drug effects*; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*
D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D012701:Serotonin