Norepinephrine-induced phasic activity in tail arteries from genetically hypertensive rats.

J. H. Myers, F. S. Lamb, R. C. Webb

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

The effects of norepinephrine on contractile force development were studied in tail artery strips from spontaneously hypertensive stroke-prone (SHRSP) and Kyoto-Wistar normotensive rats (WKY). The strips were mounted in physiological salt solution between a fixed base and force transducers; isometric contractions were recorded. Norepinephrine-induced were characterized by fluctuations in contractile activity, whereas contractile responses in arteries from WKY remained constant with time. The magnitude and frequency of phasic responses in SHRSP arteries varied directly with increasing concentrations of norepinephrine (1.8 X 10(-9) to 1.8 X 10(-6) M). The phasic responses induced by norepinephrine in SHRSP arteries were reversed by the following experimental interventions: 1) 10(-4) M ouabain; 2) 20 degrees C; 3) potassium-free solution; 4) 1.0 mM BaCl2; 5) 20 mM KCl; 6) 30 mM tetraethylammonium chloride; 7) chloride-free solution; and 8) 10(-7) M D 600 (calcium channel blocker). It is proposed that the phasic contractile responses to norepinephrine in SHRSP are related to altered movements of calcium and potassium across the cell membrane. This study demonstrates a very distinct functional individuality in the arterial vascular smooth muscle cell membrane of SHRSP.

Original languageEnglish (US)
Pages (from-to)H419-23
Number of pages5
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume248
Issue number3 Pt 2
StatePublished - Mar 1 1985

ASJC Scopus subject areas

  • Medicine(all)

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