Caffeine effects on buccal muscles of Aplysia.

Gole D, Munday L, Kreiman M, Ram J L

Department of Physiology, Wayne State University, Detroit, MI 48201.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1987;88(2):313-8. doi: 10.1016/0742-8413(87)90127-7.

Abstract

Caffeine (35-70 mM) elicited contractions of Aplysia buccal muscle El. In a Ca2+-free medium, in which ACh-elicited contractions rapidly fail, caffeine elicited contractions of approximately the same size as in normal medium. 2. 5-HT (10(-8) M and 10(-7) M) did not enhance caffeine-elicited contractions. 3. Lower concentrations (1-10 mM) of caffeine inhibited ACh-elicited contractions. Caffeine (7 mM) reduced the contraction by 80%. 4. Caffeine (7 mM) reduced ACh-elicited depolarization by 60%. 5. Caffeine (7 mM) increased 45Ca2+ influx into Aplysia buccal muscle I5. The stimulation of influx of 45Ca2+ by 10(-3) M ACh was non-additive with the stimulation caused by caffeine, and 7 mM caffeine reduced the influx caused by 10(-3) M ACh.

摘要