CELLULAR PATHWAYS OF THE CONDUCTED ELECTRICAL RESPONSE IN ARTERIOLES OF HAMSTER-CHEEK POUCH IN-VITRO

We have previously shown that conducted vasomotor reponses follow patt erns that are consistent with a passive spread of electrical current a long the length of the arterioles [(Xia and Duling, Am. J. Physiol. 26 9 (Heart Circ. Physiol. 38): H2022-H2030, 1995]. In this study, we def ine the cells through which the current flows. Isolated arterioles of hamster cheek pouch were used. The mean resting membrane potential (RM P) for randomly sampled arteriolar cells was -67 mV. When cell types w ere identified by dye injection, the RMPs were -68 and -67 mV for smoo th muscle (SM) and endothelium (EC), respectively. Pulses of KCl induc ed transient, monophasic depolarizations at the site of stimulation (l ocal), which were conducted decrementally along the length of the arte riole over several millimeters. During electrical conduction, three pa tterns of responses could be observed, but identical patterns of the c onducted electrical responses were always observed in SM and EC. Pheny lephrine stimulation also caused transient local and conducted depolar izations in both SM and EC. As with KCI stimuli, shapes of conducted e lectrical responses were identical in records made in both cell types. The results suggest that SM and EC are electrically coupled both homo cellularly and heterocellularly.