[Preliminary studies on the characterization of adenylate cyclase from segmental ganglia of the leech Hirudo medicinalis].

Adenylate cyclase activity has been measured in segmental ganglia of the leech Hirudo m. Basal enzymatic activity was stimulated in a dose dependent fashion by serotonin. GTP is required in order to evoke maximal stimulation. The effect was blocked by methysergide, an antagonist of serotonin at receptor level. The stimulation of the enzyme was prevented by alpha beta-methy-len-ATP. In addition RMI 12330A inhibited basal as well as serotonin-stimulated adenylate cyclase activity presumably by acting at the catalytic subunit level.