Premium
POTASSIUM‐INDUCED DEPOLARIZATIONS AND GENERATION OF TENSION IN BARNACLE MUSCLE FIBRES: EFFECTS OF EXTERNAL CALCIUM, STRONTIUM AND BARIUM
Author(s) -
Luxoro M.,
Nassar-Gentina Verónica
Publication year - 1984
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1984.sp002802
Subject(s) - calcium , strontium , potassium , muscle contracture , barium , chemistry , biophysics , contraction (grammar) , muscle contraction , anatomy , endocrinology , biology , inorganic chemistry , organic chemistry
Potassium‐induced contractions were studied in muscle fibres from Megabalanus psittacus (Darwin) in an attempt to establish the requirement of extracellular calcium for the development of force. A sudden elevation of external potassium induced the production of contractures and/or twitches only if calcium was present. In calcium‐free solutions no contraction or action potential occurred. When external calcium was replaced by barium, potassium‐induced depolarizations accompanied by several action potentials did not generate either contractures or twitches. With strontium in place of calcium, action potentials of different duration were observed. Only the long‐lasting ones (a few seconds) induced twitches.