Identification of a 5-HT1A receptor positively coupled to planarian adenylate cyclase

The adenylate cyclase system present in particulate fractions prepared from two planarian species was tested for sensitivity to various neurotransmitters. While dopamine and other catecholamines were ineffective, serotonin was capable of stimulating the enzyme. Among the various serotonin agonists tested, only 8-OH-DPAT resulted effective on the adenylate cyclase activity, thus suggesting the presence in planarians of a serotonin receptor of the type 5-HT1A.