The effect of warming on adrenergic neurotransmission in canine cutaneous vein

John P. Cooke, J. T. Shepherd, P. M. Vanhoutte

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

The effect of warming on adrenergic neurotransmission was examined in canine cutaneous veins. Isometric tension was recorded from rings of saphenous veins of the dog in organ chambers filled with physiological salt solution. During contractions caused by potassium or prostaglandin F(2α), warming from 37 to 41° C caused an augmentation. During contractions caused by stimulation of the adrenergic nerves, and by exogenous norepinephrine, warming caused a relaxation. The relaxation with warming was not altered by the β-adrenergic antagonists, propranolol, or by inhibitors of extraneuronal and neuronal uptake of norepinephrine. During contractions evoked by the α2-adrenergic agonists, α-methyl norepinephrine and B-HT 920, warming caused a relaxation, whereas during contractions due to the α1-adrenergic agonists, cirazoline, methoxamine, ST 587, and phenylephrine, it caused an augmentation. The relaxation caused by warming during norepinephrine-induced contractions was prevented by the preferential α2-antagonists yohimbine and rauwolscine, but not by the preferential α1-antagonist, prazosin. In strips of saphenous vein incubated with [3H]norepinephrine, warming did not affect the release of labeled transmitter evoked by nerve stimulation. These experiments indicate that warming directly enhances contractility of vascular smooth muscle, while depressing the responsiveness of cutaneous vessels to sympathetic nerve activation by a selective inhibitory effect on postjunctional α2-adrenoceptors. Relaxation with warming is greater during nerve stimulation than during administration of exogenous norepinephrine, which may be due to a predominance of postjunctional, α2-adrenoceptors in the neuromuscular junction.

Original languageEnglish (US)
Pages (from-to)547-553
Number of pages7
JournalCirculation Research
Volume54
Issue number5
DOIs
StatePublished - Jan 1 1984

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'The effect of warming on adrenergic neurotransmission in canine cutaneous vein'. Together they form a unique fingerprint.

Cite this