Adenosine receptor agonists inhibit the release of gamma-aminobutyric acid (GABA) from the ischemic rat cerebral cortex.

Abstract

The effects of CPA (a selective A1 receptor agonist), NECA (a mixed A1 and A2 receptor agonist), and CGS 21680 (a selective A2 receptor agonist) on the ischemia-evoked release of gamma-aminobutyric acid (GABA) from rat cerebral cortex was investigated with the cortical cup technique. Cerebral ischemia (20 min) was elicited by four vessel occlusion. In control animals, superfusate GABA increased from a basal level of 206 +/- 26 nM (mean +/- S.E.M., n = 18) to 10,748 +/- 3,876 nM during the reperfusion period. Pretreatment with adenosine receptor agonists failed to affect basal levels of GABA release. However, CPA (10(-10) M), NECA (10(-9) M), and CGS 21680 (10(-8) M) significantly suppressed the ischemia-evoked release of GABA. The ability to block the ischemia-evoked release of GABA was not evident when the adenosine receptor agonists were administered at higher concentrations. Thus, the selective activation of either A1 or high-affinity A2a adenosine receptors results in an inhibition of ischemia-evoked GABA release.

• Authors: M H O'Regan, R E Simpson, L M Perkins, J W Phillis
• Journal: Brain research (Brain Res) Vol. 582 Issue 1 Pg. 22-6 (Jun 05 1992) ISSN: 0006-8993 [Print] Netherlands
• PMID: 1498681 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Phenethylamines
• Receptors, Purinergic
• 2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine
• Adenosine-5'-(N-ethylcarboxamide)
• N(6)-cyclopentyladenosine
• gamma-Aminobutyric Acid
• Adenosine

Topics

• Adenosine (analogs & derivatives, pharmacology)
• Adenosine-5'-(N-ethylcarboxamide)
• Analysis of Variance
• Animals
• Cerebral Cortex (drug effects, metabolism)
• Dose-Response Relationship, Drug
• Electroencephalography
• Ischemic Attack, Transient (metabolism, physiopathology)
• Kinetics
• Male
• Phenethylamines (pharmacology)
• Rats
• Rats, Inbred Strains
• Receptors, Purinergic (drug effects, physiology)
• Time Factors
• gamma-Aminobutyric Acid (metabolism)