Role of metabolism in K-induced tension changes in guinea pig taenia coli

¹ Department of Pharmacology, University of Mississippi School of Medicine, Jackson, Mississippi

Further insight into the underlying mechanism(s) of the K-induced phasic and tonic contractions of the taenia coli of the guinea pig was obtained by examining the effects of various metabolic intermediates, inhibitors of metabolism and active transport, on these responses. Evidence is presented to support the thesis that the tonic response is dependent on the aerobic breakdown of carbohydrates and is abolished by substrate removal, a decrease of temperature, DNP, lithium, and ouabain. These same factors have little or no effect on the phasic response. From the evidence presented, it is concluded that the phasic response is a passive process, whereas the tonic contracture is an active one depending on metabolism and possibly linked to active Na transport.

Key Words: smooth muscle • tonic contracture • phasic contracture • Na-Ca pump • metabolic inhibitors • active transport • inhibitors • anoxia • temperature

Submitted on November 2, 1964

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