FURTHER EVIDENCE THAT VARIOUS 5-HT RECEPTOR SUBTYPES MODULATE CENTRALRESPIRATORY ACTIVITY - IN-VITRO STUDIES WITH SR 46349B

The ability of SR 46349B oethyl)oxyimino-3(2-flurophenyl)propen-1-yl]p henol hemifumarate), a 5-HT2 receptor antagonist, to block the changes in respiratory activity induced by serotonin was analysed by using br ain stem-spinal cord preparations from newborn rats. The increases in respiratory frequency elicited by serotonin (and 5-HT1A receptor agoni st) were not suppressed by SR 46349B. The tonic discharge of cervical motoneurons and the depression of inspiratory hypoglossal activity eli cited by serotonin (and 5-HT2 receptor agonist) were reduced in a dose -dependent manner by SR 46349B. These results confirm that activation of 5-HT1A and 5-HT2 receptors influences respiratory frequency and mot oneuronal output, respectively.