Abstract
Since Dale's report (1) on a hypothetical role of histamine in anaphylactic shock, the view that the histamine plays as an important chemical mediator in allergic reaction has been steadily supported by many investigators (2-10). Antihistaminics are now widely applied in allergy clinics to suppress the action of histamine produced endogenously by antigen-antibody reaction. The therapeutic effect of antihistaminics on allergic diseases is believed to be ascribed to the competition with histamine on histamine-receptor (11, 12) the drugs never acting on the immunological process itself (13). It is also acknowledged that allergic symptomes do not entirely disappear even after the administration of antihistaminics (14-16). On the other hand, it has been noted that several substances besides histamine were found to play roles in allergic shock and that antihistaminics had many pharmacological actions, in addition to antihistaminic action (17-23). Previously, Okamura (24) reported that anaphylactic contraction of taenia coli from guinea pig was dependent on the electric smooth muscle cell membrane potential. It has consequently been assumed that examination of the influence of spasmolytic drugs on membrane potential will not only have important implication for the elucidation of anaphylactic contraction, but also provede valuable clues for future study of anti-allergic drugs. In the present paper, antihistaminics were compared with adrenaline, papaverine and atropine for the purpose of elucidating the antihistaminics' inhibitory action on anaphylactic contraction in guinea pig's taenia coli using an electrophysiological method.
