@article {WEISS43, author = {GEORGE B. WEISS}, title = {ON THE SITE OF ACTION OF NICOTINE ON CONTRACTURE IN FROG SARTORIUS MUSCLE}, volume = {163}, number = {1}, pages = {43--53}, year = {1968}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Several experimental approaches were utilized to obtain information concerning the mechanism by which nicotine acts to alter Ca45 movements and induce contracture in frog sartorius muscle. Nicotine elicited an increased Ca45 efflux only when EDTA was present in a Ca-free Ringer{\textquoteright}s bathing solution. Substitution of nitrate anion for chloride resulted in a potentiation of nicotine contracture but no additional Ca45 uptake as measured by Ca45 spaces after a 120-min washout. Increasing the potassium concentration to 80 mM markedly increased nicotine-C14 efflux but did not significantly alter the nicotine-C14 tissue space occupied. Neither nitrate anion nor 80 mM K+ altered intracellular pH as measured by DM0-C14 spaces. Also, high concentrations of d-tubocurarine chloride (0.3 mg/ml) did not prevent a nicotine contracture and associated increases in Ca45 uptake. These observations provide further indication that nicotine acts at sites in the transverse tubule membrane to alter Ca45 movements and induce contracture. Furthermore, these actions of nicotine may occur at calcium sites different from those at which corresponding effects are elicited by exposure to 80 mM potassium. {\textcopyright} 1968, by The Williams \& Wilkins Company}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/163/1/43}, eprint = {https://jpet.aspetjournals.org/content/163/1/43.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }