title: Calcium channel blockade: possible explanation for thioridazine's peripheral side effects.
abstract: The authors show that thioridazine possesses calcium antagonist activity which may relate to its cardiac and sexual side effects. Binding sites associated with voltage-operated calcium channels were labeled by 3H-nitrendipine. Thioridazine influenced this binding of 3H-nitrendipine in a fashion similar to known calcium antagonists such as verapamil. Thioridazine also antagonized potassium-induced, calcium-dependent contractions of rat vas deferens, with similar potency. Thioridazine concentrations that exert calcium channel antagonist effects correspond to blood levels at therapeutic doses.
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D002121:Calcium Channel Blockers / Q000378:metabolism; D004542:Ejaculation / Q000187:drug effects*; D005260:Female; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009543:Nifedipine / Q000031:analogs & derivatives / Q000378:metabolism; D009568:Nitrendipine; D011437:Propylamines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012735:Sexual Dysfunction, Physiological / Q000139:chemically induced; D013881:Thioridazine / Q000009:adverse effects* / Q000097:blood / Q000494:pharmacology; D013976:Tiapamil Hydrochloride; D014649:Vas Deferens / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D007473:Ion Channels; D011437:Propylamines; D009568:Nitrendipine; D014700:Verapamil; D009543:Nifedipine; D013881:Thioridazine; D013976:Tiapamil Hydrochloride