Prejunctional adrenergic inhibition by aggregating platelets in canine blood vessels

Am J Physiol. 1985 Sep;249(3 Pt 2):H685-9. doi: 10.1152/ajpheart.1985.249.3.H685.

Abstract

Experiments were performed to determine the effect of aggregating platelets on adrenergic neurotransmission. Rings of canine saphenous veins and left circumflex coronary arteries were incubated with [3H]norepinephrine and suspended for superfusion. Aggregating platelets and exogenous 5-hydroxytryptamine decreased the overflow of [3H]norepinephrine evoked by electrical stimulation of the adrenergic nerve endings. The reduction of transmitter overflow caused by 5-hydroxytryptamine was prevented by the serotonergic antagonist methiothepin in a concentration that did not significantly affect the release of 5-hydroxytryptamine or thromboxane B2 from the aggregating platelets. Methiothepin decreased but did not abolish the inhibitory effect of aggregating platelets on neurotransmitter overflow. These experiments demonstrate that 5-hydroxytryptamine and other substances released from aggregating platelets can exert prejunctional inhibition of adrenergic neurotransmission in isolated blood vessels.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Platelets / metabolism
  • Coronary Vessels / physiology*
  • Dogs
  • Electric Stimulation
  • In Vitro Techniques
  • Methiothepin / pharmacology
  • Muscle Contraction
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology*
  • Norepinephrine / physiology*
  • Phentolamine / pharmacology
  • Platelet Aggregation / drug effects*
  • Saphenous Vein / physiology*
  • Serotonin / blood
  • Serotonin / pharmacology*
  • Thromboxane B2 / blood

Substances

  • Serotonin
  • Thromboxane B2
  • Methiothepin
  • Norepinephrine
  • Phentolamine