Abstract
In a previous report (1) it was shown that in guinea pig taenia coli hypertonically added 40 mM K induced a large tension and that both tissue Ca and 45Ca uptake of the muscle measured after a 4 minutes wash increased, while in 152 mM K/0 mM Na medium only a small tension remained and 45Ca uptake did not increase while tissue Ca decreased. It has also been shown that the tonic response in hypertonic 40 mM K medium is dependent on aerobic breakdown of carbohydrates and blocked by sodium transport inhibitor (2-4). The tonic response in 152 mM K/0 mM Na medium was however shown to be unaffected by a sodium transport inhibitor and not solely dependent on aerobic breakdown of carbohydrates (4).
The present investigation is concerned with the changes in tension, uptake of 45Ca measured after a 4 minutes wash and tissue Ca in varying concentrations of Na and K in the external medium, and also the effects of inhibitors of metabolism and sodium transport in guinea pig taenia coli.
A part of this work has already been represented (5).
