The role of calcium in initiating smooth muscle contraction is widely documented. The intracellular sinks and sources of activator calcium have not been clearly delineated although SR, mitochondria and plasma membrane have been suggested as possible sites of calcium sequestration. It has been previously proposed that spasmolytic agents exert at least part of their relaxing effect by altering normal calcium movements into calcium sinks and/or out of the calcium sources. In this grant proposal a method is presented with which the distribution of calcium among intracellular structures can be determined. This method involves the electron microscopic examination of freeze-dried, smooth muscle that has been prepared for 45Ca autoradiography. By employing these techniques, we propose to examine the effects of smooth muscle spasmogenic and spasmolytic agents on the distribution of calcium among intracellular structures. We anticipate that an analysis of these data will help us to more clearly understand how these pharmacological agents exert their physiological effects on smooth muscle.
McGuffee, L J; Little, S A; Mercure, J V et al. (1990) Effects of temperature and buffer composition on calcium sequestration by sarcoplasmic reticulum and plasma membrane of rabbit renal artery. Anat Rec 228:288-96 |
McGuffee, L J; Little, S A; Skipper, B J (1987) Localization of calcium in vas deferens using 45Ca EM autoradiography: relationship to species and the effect of 45Ca removal. Anat Rec 217:321-7 |
Jorgensen, A O; McGuffee, L J (1987) Immunoelectron microscopic localization of sarcoplasmic reticulum proteins in cryofixed, freeze-dried, and low temperature-embedded tissue. J Histochem Cytochem 35:723-32 |
McGuffee, L J; Wheeler-Clark, E S; Skipper, B J et al. (1985) The cellular distribution of calcium in freeze-dried rabbit vas deferens using EM autoradiography. Anat Rec 211:117-25 |
Skipper, B J; McGuffee, L J (1985) Statistical significance tests for autoradiographic data. Anat Rec 211:126-32 |