title: Organic calcium channel blockers enhance [3H]purine release from rat brain cortical synaptosomes.
abstract: The release of [3H]purines was investigated in a crude mitochondrial fraction (P2 fraction) from rat brain cortex pre-loaded with [3H]adenosine for 30 sec at 37 degrees C in vitro. Potassium, veratridine and glutamate were used as depolarizing agents to evoke the release of [3H]purines. Ca2+ removal, the addition of EGTA, and treatment with organic or inorganic Ca2+ antagonists did not inhibit [3H]purine release in this preparation. On the other hand, Ca2+ removal and the addition of EGTA greatly enhanced 3H-purine release induced by glutamate. D-600 and diltiazem enhanced K+-evoked [3H]purine release, and nifedipine increased veratridine evoked [3H]purine release indicating that either these Ca2+ antagonists have different sites of action, or that K+ and veratridine may release [3H]purine from different metabolic pools. Organic Ca2+ antagonists failed to enhance the [3H]purine release evoked by glutamate, further supporting the notion that various depolarizing agents may release [3H]purines from different cellular compartments.
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000378:metabolism*; D004110:Diltiazem / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011687:Purines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D005971:Glutamates; D011687:Purines; D005711:Gallopamil; D018698:Glutamic Acid; D004533:Egtazic Acid; D014701:Veratridine; D004110:Diltiazem; D009543:Nifedipine; D000241:Adenosine; D011188:Potassium; C030985:purine