Assay of catecholamines on the isolated transverse stomach strip of the rabbit

Isolated transverse stomach strip of the rabbit was contracted by low concentrations (10(-10) M) of noradrenaline and adrenaline. The contractions were competitively inhibited by phentolamine. Other agonists, such as acetylcholine, histamine, 5-HT, angiotensin II, bradykinin and PGF2 alpha also caused contractions which could be blocked by their specific antagonists. This smooth muscle preparation was more sensitive to noradrenaline and adrenaline than to the other agonists used. Dopamine also produced a contraction when higher concentrations (above 10(-5) M) were used. No tachyphylaxis or spontaneous rhythmicity was observed to repeated application of noradrenaline and adrenaline. It is concluded that rabbit transverse stomach strip could be useful preparation for the bioassay of these catecholamines.