Effects of the small cardioactive peptide B (SCPB) on adenylate cyclase of the central nervous system and peripheral organs of the freshwater snail Planorbarius corneus.
The effect of the small cardioactive peptide B (SCPB) on adenylate cyclase activity of the central nervous system (CNS) and some peripheral organs of the freshwater snail Planorbarius corneus was investigated. This peptide stimulates enzyme activity in a dose-dependent manner in all the tested ganglia, in the salivary glands, the buccal mass and the oesophagus. The amount required for half-maximal stimulation is approx 0.1 microM. Moreover, the response of adenylate cyclase to SCPB progressively increases with time, without desensitizing. On the other hand, the peptide is ineffective on heart adenylate cyclase. The responsiveness of adenylate cyclase activity to the peptide and the wide distribution of SCPB-related immunoreactivity in all the tested ganglia suggest that this substance may exert an important role as neurotransmitter as well as neuromodulator in the CNS of the snail. Since SCPB is consistently present in the buccal and cerebral ganglia, associated nerves, salivary glands, buccal mass and oesophagus, and in the light of the appreciable effects exerted by SCPB on adenylate cyclase activity in the examined peripheral tissues, we suggest that the peptide is strongly involved in the control of feeding behaviour of P. corneus.
Istituto di Fisiologia Geneale, Università di Ferrara, Italy.
M E
ME
Ferretti
D
D
Sonetti
M C
MC
Pareschi
C
C
Biondi
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002610:Cheek; D000242:Cyclic AMP / Q000378:metabolism; D004947:Esophagus / Q000187:drug effects / Q000201:enzymology; D005724:Ganglia / Q000187:drug effects / Q000201:enzymology; D007700:Kinetics; D009420:Nervous System / Q000187:drug effects / Q000201:enzymology; D009479:Neuropeptides / Q000494:pharmacology*; D012469:Salivary Glands / Q000187:drug effects / Q000201:enzymology; D012908:Snails / Q000187:drug effects / Q000201:enzymology*
D009479:Neuropeptides; C041307:small cardioactive peptide B; D000242:Cyclic AMP; D000262:Adenylyl Cyclases