Actions of Kavain and Dihydromethysticin on Ipsapirone-Induced Field Potential Changes in the Hippocampus.

The kava-pyrones kavain and dihydromethysticin are constituents of Piper methysticum which possess muscle relaxant, anticonvulsant, analgesic and anxiolytic properties. In the present study the effect of both kava-pyrones were tested on field potential changes induced by the serotonin-1A agonist ipsapirone in the area CA1 and CA3 of the hippocampal slice preparation of guinea pigs. Ipsapirone induced positive field potential changes which were decreased in amplitude by the serotonin-1A antagonist NAN. The ipsapirone response was reduced by extracellular administration of kavain and dihydromethysticin in a dose-dependent manner down to 22·2 and 33·6%, respectively. It is suggested that kavain and dihydromethysticin modulate serotonin-1A receptor activity which may be of importance in the anti-anxiety action of kava-pyrones. © 1997 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]