Modulation by alpha 2-adrenergic stimulation of IgE-mediated 14C-serotonin release from rat mast cells

Agents Actions. 1983 Jun;13(4):310-7. doi: 10.1007/BF01971482.

Abstract

The formaldehyde method was used to examine the effects of clonidine and methoxamine on IgE-mediated 14C-serotonin release from rat mast cells in vitro. Clonidine (10(-11) -10(-8) M) caused dose-related enhancement of the mediator release 7 min after the antigen challenge; yohimbine (10(-6) M) blocked this enhancement by clonidine (10(-6) M), but prazosin (10(-6) M) did not. Methoxamine did not enhance this immunological release reaction at concentrations up to 10(-6) M. PGE1 (2 X 10(-8) -2 X 10(-5) M), isoproterenol (10(-10) -10(-8) M), dopamine (4 X 10(-8) -4 X 10(-8) M) and aminophylline (6 X 10(-6) -6 X 10(-4) M) caused dose-related inhibition of this mediator release 1 min after antigen challenge. Clonidine (10(-13) -10(-12) M), but not methoxamine (10(-8) -10(-6) M), reversed dose-dependently this inhibition of mast cells by PGE1 (2 X 10(-6) M), isoproterenol (10(-8) M), dopamine (4 X 10(-6) M); yohimbine (10(-8) M) antagonized this reversing action of clonidine (10(-12) M), but prazosin (10(-10) M) did not. Neither clonidine (10(-14) -10(-11) M) nor methoxamine (10(-8) -10(-6) M) reversed the inhibitory action of aminophylline (2 X 10(-4) M). These results suggests that clonidine enhances IgE-mediated 14C-serotonin release from rat mast cells and also antagonizes the inhibition of mast cells by PGE1, isoproterenol and dopamine, but not by aminophylline in this immunological reaction through alpha 2-adrenergic receptors, and that the inhibition of adenylate cyclase of mast cells is one of the biochemical actions of alpha 2-adrenergic mechanisms.

MeSH terms

  • Adrenergic alpha-Agonists / pharmacology*
  • Alprostadil
  • Animals
  • Clonidine / pharmacology
  • Female
  • Immunoglobulin E / physiology*
  • Isoproterenol / pharmacology
  • Male
  • Mast Cells / drug effects
  • Mast Cells / metabolism*
  • Methoxamine / pharmacology
  • Mice
  • Mice, Inbred BALB C
  • Prostaglandins E / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Serotonin / metabolism*
  • Yohimbine / pharmacology

Substances

  • Adrenergic alpha-Agonists
  • Prostaglandins E
  • Yohimbine
  • Serotonin
  • Immunoglobulin E
  • Alprostadil
  • Methoxamine
  • Isoproterenol
  • Clonidine