The A1 agonist CCPA reduced bisoxonol-monitored membrane potential depolarization elicited by high K+ in cerebrocortical nerve endings.
In this study the effect of the A1 agonist 2-chloro-N6-cyclopentyladenosine (CCPA) on bis(1,3-diethylthiobarbituric acid)trimethine oxonol (bisoxonol)-monitored membrane potential in cerebrocortical nerve endings was evaluated. CCPA (30, 100 and 300 microM) caused a dose-dependent decrease of high K(+)- and veratridine-induced membrane depolarization. This decrease was counteracted by the A1-specific antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) (30-100 microM). On the contrary, the A2 receptor antagonist 9-chloro-2-(2-furanyl)-5,6-dihydro-1,2,4-triazolol-[1,5-c]quinazol ine-5- imine (CGS 15943) was unable to interfere with the lowering effect exerted by CCPA (100 microM) on K(+)-elicited membrane depolarization. Finally, the A2 receptor agonist 2-[p-(2-carboxyethyl)phenethylamine]-5'-N-ethylcarboxamidoadenosine (CGS 21680) did not induce any modification of K(+)-induced membrane depolarization. The results of the present study suggest that K(+)-induced membrane depolarization in cerebrocortical brain nerve endings may be modulated by A1 receptors.
Amoroso
S
S
Department of Neuroscience, School of Medicine, Federico II, University of Naples, Italy.
Iannotti
E
E
Saggese
M L
ML
Di Renzo
G
G
Annunziato
L
L
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002540:Cerebral Cortex; D005456:Fluorescent Dyes; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009411:Nerve Endings / Q000502:physiology*; D010627:Phenethylamines / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D011799:Quinazolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013574:Synaptosomes / Q000502:physiology*; D013858:Thiobarbiturates; D014230:Triazoles / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D005456:Fluorescent Dyes; D010627:Phenethylamines; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D011799:Quinazolines; D013858:Thiobarbiturates; D014230:Triazoles; D014970:Xanthines; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C058394:2-chloro-N(6)cyclopentyladenosine; C025284:bis(1,3-diethylthiobarbiturate)trimethineoxonol; D014701:Veratridine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000241:Adenosine; D011188:Potassium; C052410:9-chloro-2-(2-furyl)-(1,2,4)triazolo(1,5-c)quinazolin-5-imine