Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 351, Issue 5, pp 483–490

Facilitation of noradrenaline release from rat brain slices by \-adrenoceptors

  • Kamala D. Murugaiah
  • James M. O'Donnell
Original Article

DOI: 10.1007/BF00171039

Cite this article as:
Murugaiah, K.D. & O'Donnell, J.M. Naunyn-Schmiedeberg's Arch Pharmacol (1995) 351: 483. doi:10.1007/BF00171039

Abstract

The present study examined whether stimulation of \-adrenoceptors facilitated noradrenaline release in the rat brain. Electrical stimulation-evoked overflow of tritium from rat cerebral cortical, hypothalamic and hippocampal slices labelled with 3H-noradrenaline was measured during superfusion for 100 min. Tissue slices were electrically simulated (1 Hz, 20 mA, 2 ms, 2 min), at 20(S1) and 70(S2) min after the onset of superfusion. The nonselective \-adrenoceptor agonist isoproterenol (0.1 – 10 nM) enhanced stimulation-evoked overflow of tritium from slices of cerebral cortex, hypothalamus and hippocampus in a concentration-dependent manner; mean S2/S1 ratios with 10 nM isoproterenol were 161 +- 11%, 142 +- 15% and 143 - 12% of control, respectively, in the three brain regions. The facilitatory effect of isoproterenol in cerebral cortical slices was antagonized by propranolol (50 nM), a nonselective \sb-adrenoceptor antagonist, and by the \sb1- and \sb2-selective adrenoceptor antagonists ICI 89,406 (1 nM) and ICI 118,551(1 nM), respectively. The \sb1- and \sb2-selective adrenoceptor agonists prenalterol and albuterol (0.1 \2- 10 nM), respectively, also increased stimulation-evoked overflow of tritium from cerebral cortical slices; these effects were antagonized by \sb-adrenoceptor antagonists. These findings suggest that stimulation of \sb-adrenoceptors enhance noradrenaline release from rat cerebral cortical, hypothalamic and hippocampal slices; this release mechanism appears to involve both \sb1- and \sb2-adrenoceptor subtypes. These facilitating presynaptic receptors may be involved in mediating the antidepressant-like behavioral effects of \sb2-adrenoceptor agonists.

Key words

Noradrenaline release\-Adrenoceptors FacilitationPresyaptic receptorsRegulation Isoproterenol\-Adrenoceptor subtypes

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Kamala D. Murugaiah
    • 1
  • James M. O'Donnell
    • 1
  1. 1.Department of Pharmacology and Therapeutics Louisiana State University Medical School ShreveportLouisianaUSA