Abstract

Preliminary studies showed that dorsal artery contraction mediated by acetylcholine (ACh) is blocked with indomethacin in intertidal fish (Girella laevifrons). Our objective was to characterise the cholinergic pathway in several artery vessels of the G. laevifrons. Afferent and efferent branchial, dorsal and mesenteric arteries were dissected of 6 juvenile specimens, isometric tension studies were done using dose response curves (DRC) for Ach (10(-13) to 10(-3) M), and cholinergic pathways were obtained by blocking with atropine or indomethacin. CRC to ACh showed a pattern of high and low sensitivity. Furthermore, these contractions were blocked in the presence of atropine and indomethacin in all vessels. Our results suggest that contraction observed with acetylcholine is mediated by receptors that activate a cyclooxygenase contraction pathway.