Regulation of Smooth Muscle Responsiveness
Final rept. 1 Nov 1965-1 Nov 1970
NEW YORK MEDICAL COLL NY
Pagination or Media Count:
Intracellular recording of electrical activity from vascular smooth muscle superior mesenteric vein of the Guinea pig has been made a routine experiment, maintaining impalement during spontaneous and drug induced activity. Normal spontaneous activity and the effects of catecholamines, acetylcholine and ions have been studied in terms of electrical and mechanical activity. Voltage clamp and constant current injection techniques have been used to investigate the membrane properties of vascular and other smooth muscle. Effects of 2-4- dinitrophenoland CN- have been studied in terms of electrical activity. Attempts have also been made to record electrical activity from the precapillary sphincters of rat mesentry. The above studies indicate that although the electrical properties of the smooth muscle membrane may be somewhat similar to those of nerve and striated muscle, the ionic mechanisms may differ essentially, e.g., the excitation of smooth muscle from the longitudinal layer of the superior meserteric vein and also taenia coli of the guinea pig is Ca dependent, Tetrodotoxin TTX insensitive and is blocked by transition metals. By using TTX the involvement of local reflexes axon reflex participating in the phenomenon has been excluded.
- Anatomy and Physiology