+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrophysiological effects of tetracaine on the longitudinal muscle of rat uterus in various ionic environments

Japanese Journal of Physiology 37(5): 851-869

Electrophysiological effects of tetracaine on the longitudinal muscle of rat uterus in various ionic environments

Electrical activity was recorded intracellularly from the uterine longitudinal muscle of estrogen-treated rat. Membrane potential was -59 mV. Action potential consisted of initial spike and the following plateau potential on which repetitive spike discharge rode. Tetracaine (0.1, 0.2 mM) reduced the maximum rates of rise and fall of initial spike and increased the duration of plateau potential. Sustained depolarization at -33 mV was produced by the application of 0.8 mM tetracaine. The membrane depolarization was accompanied with the increase in membrane resistance. Reduction of initial spike by tetracaine in the maximum rates of rise and fall was prevented by increasing the external Ca concentration and accelerated by decreasing it. In low K (1.2 mM) or isoprenaline (10(-8) M)-containing solution, tetracaine-induced prolongation of plateau potential was inhibited. Plateau potential was reduced in amplitude and was prolonged only slightly by tetracaine in low Na solution (sucrose substitution). Both the initial spike and plateau potentials were blocked completely by 0.2 mM tetracaine in the presence of Mn (0.5 mM) or verapamil (0.5 microM). It is speculated that tetracaine suppresses the K conductances responsible for resting membrane potential and the repolarizations of spike and plateau potentials. Ca influx during the generation of action potential is also supposed to be inhibited by tetracaine.

(PDF 0-2 workdays service: $29.90)

Accession: 005349600

PMID: 3449665

Related references

Ionic currents in longitudinal muscle of the uterus. Buelbring, E Et Al (Ed ) Smooth Muscle: An Assessment Of Current Knowledge Xii+563p Edward Arnold Publishers, Ltd : London, England Illus P353-366, 1981

The effects of phenylephrine in various ionic environments on the circular muscle of mid-pregnant rat myometrium. Japanese Journal of Physiology 28(5): 627-645, 1978

A comparison of the effects of various smooth muscle relaxants on the electrical and mechanical activity of rat uterus epinephrine relaxant papaverine relaxant tetracaine relaxant nitro glycerin relaxant. Journal of Pharmacology and Experimental Therapeutics 168(1): 21-30, 1969

The effects of estrogen on the ionic channels in single smooth muscle cells of pregnant rat uterus. Japanese Journal of Physiology 43(SUPPL 2): S168, 1993

Comparison of ionic effects on longitudinal and circular muscle of jejunum. Physiologist 13(3): 228, 1970

Comparison of ionic effects on longitudinal and circular muscle of cat jejunum. American Journal of Physiology 226(5): 1212-1218, 1974

Electrophysiological effects of tetracaine in single guinea-pig ventricular myocytes. Journal of Physiology 376: 143-161, 1986

The effects of different ionic environments on the intra cellular cation concentrations and on the membrane potential of tenia coli smooth muscle. Int Union Pharmacoledings Of The International Congress Of Pharmacology, 6th. Abstract. Helsinki, Finland, . 632illus. Pergamon Press: Oxford, Engl.; New York, N.y., Usa. Isbn 0-08-021308-1. 54, 1977

Electrophysiological comparison between the longitudinal and circular muscles of the rat uterus during the estrous cycle and pregnancy. Japanese Journal of Physiology 28(2): 197-209, 1978

Effects of short- and long-term administration of ritodrine on spontaneous contractions of longitudinal muscle strips dissected from the pregnant rat uterus. Nihon Sanka Fujinka Gakkai Zasshi 42(6): 605-611, 1990