5-HT receptors on identified Lymnaea neurones in culture: pharmacological characterization of 5-HT3 receptors.
1. The selective agonist, 1-(m-chlorophenyl)-biguanide (m-CPBG) and antagonist, 3-tropanyl-3,5-dichlorobenzoate (MDL 72222) were used to characterize the 5-HT3 receptors in cultured identified neurones; the serotonin-containing cerebral giant cells (CGCs) and some follower neurones in the buccal ganglia of Lymnaea stagnalis. 2. 5-HT and its agonists were pressure ejected, while the 5-HT antagonists were bath applied. 3. Although m-CPBG evoked mostly depolarizing responses, hyperpolarizing responses were sometimes evoked. 4. At 10(-4) M, m-CPBG failed to mimic the responses of 5-HT, but at a concentration higher, 10(-3) M, pressure-ejected m-CPBG mimicked most 5-HT responses. 5. The 5-HT2 antagonist ketanserin failed to block the m-CPBG-evoked responses, whilst partially blocking the 5-HT responses. 6. These results suggest the presence of 5-HT3 receptors similar to those found in mammalian neurones, and that multiple subtypes of these receptors may be present in Lymnaea neurones.
Walcourt-Ambakederemo
A
A
Department of Physiology, University of Leeds, U.K.
Winlow
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W
D000818:Animals; D001645:Biguanides / Q000494:pharmacology; D002478:Cells, Cultured; D007650:Ketanserin / Q000494:pharmacology; D008195:Lymnaea / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014326:Tropanes / Q000494:pharmacology
D001645:Biguanides; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D014326:Tropanes; D012701:Serotonin; C065734:1-(3-chlorophenyl)biguanide; D007650:Ketanserin; C042253:bemesetron