Abstract
The area postrema (AP) has been considered to play an important role in controlling the antonomic functions. We found that ACh evoked an inward current at a holding potential of -70mV in acutely dissociated AP neurons of rat, using the whole cell patch clamp method. The ACh-induced current was inhibited by nicotinic antagonists, but not by atropine, and the current was also induced by nicotinic agonists. The current-voltage relationship showed a marked inward rectification. The ACh-induced current was reduced in the absence of external Na+, but was still substantial at 10mM Ca2+, suggesting some permeability to Ca2+ of receptor channel. The ACh response was significantly inhibited by serotonin, but not by noradrenaline. Serotonin did not affect the ATP-induced current. Our results indicate the presence of nicotinic receptors on AP neurons, and suggest that serotonergic nerve modifies the nicotinic transmission. [Jpn J Physiol 54 Suppl:S137 (2004)]
