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Author(s): Queiroz, G
Talaia, C
Goncalves, J
Title: ATP modulates noradrenaline release by activation of inhibitory P2Y receptors and facilitatory P2X receptors in the rat vas deferens
Issue Date: 2003
Abstract: The role of ATP on the modulation of noradrenaline release elicited by electrical stimulation (100 pulses/8 Hz) was studied in the prostatic portion of rat vas deferens preincubated with [H-3] noradrenaline. In the presence of P1 antagonists, the nucleotides 2-methylthioadenosine-5'-triphosphate (2-MeSATP), 2-methylthioadenosine 5'-diphosphate (2-MeSADP), ADP, and ATP decreased electrically evoked tritium overflow up to 44%, with the following order of potency: 2-MeSATP > 2-MeSADP > ADP greater than or equal to ATP. The P2Y antagonists reactive blue 2 (RB2) and 2-methylthioadenosine 5'-monophosphate (2-MeSAMP) increased, whereas the P2X antagonist pyridoxal-5'-phosphate-6( 2'-naphthylazo-6'-nitro-4',8'-disulfonate) (PPNDS) decreased evoked tritium overflow. The inhibitory effect of 2-MeSATP was antagonized by RB2 (10 muM) and by 2-MeSAMP (10 muM) but not by the selective P2Y1 receptor antagonist 2'-deoxy-N-6-methyladenosine 3', 5'-bisphosphate (MRS 2179; 10 muM). When, besides P1 receptors, inhibitory P2Y receptors were blocked with RB2, alpha,beta-methyleneadenosine 5'-triphosphate (alpha,beta-meATP), beta,gamma-imidoadenosine 5'-triphosphate (beta,gamma-imidoATP), beta,gamma-methyleneadenosine 5'-triphosphate (beta,gamma-meATP), 2-MeSATP, and ATP enhanced tritium overflow up to 140%, with the following order of potency: alpha,beta-meATP > 2-MeSATP = ATP = beta,gamma-meATP greater than or equal to beta, gamma-imidoATP. The facilitatory effects of alpha,beta-MeATP and beta,gamma-imidoATP were prevented by PPNDS. Under the same conditions, apyrase attenuated, whereas the ectonucleotidase inhibitor 6-N, N-diethyl-D-beta, gamma-dibromomethylene 5'-triphosphate enhanced tritium overflow, an effect that was prevented by PPNDS. In the prostatic portion of the rat vas deferens, endogenous ATP exerts a dual and opposite modulation of noradrenaline release: an inhibition through activation of P2Y receptors with a pharmacological profile similar to that of the P2Y12 and P2Y13 receptors and a facilitation through activation of P2X receptors with a pharmacological profile similar to that of P2X1 and P2X3, or PX2/P2X3 receptors.
Subject: Medicina básica
Basic medicine
Scientific areas: Ciências médicas e da saúde::Medicina básica
Medical and Health sciences::Basic medicine
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FFUP - Artigo em Revista Científica Internacional

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