caa a22 4500 469078820 CHVBK 20180323132943.0 cr unu---uuuuu 170328e19920801xx s 000 0 eng 10.1007/BF00165299 doi (NATIONALLICENCE)springer-10.1007/BF00165299 Electrophysiological and electrochemical analysis of the secretion of ATP and noradrenaline from the sympathetic nerves in rat tail artery: effects of α2-adrenoceptor agonists and antagonists and noradrenaline reuptake blockers [Elektronische Daten] [M. Msghina, C. Mermet, F. Gonon, L. Stjärne] Summary: The aim of this study was to investigate whether or not nerve impulses release ATP and noradrenaline in parallel from the sympathetic nerve terminals of the rat tail artery. The extracellularly recorded excitatory junction current (EJC) was used to study, pulse by pulse, the release of ATP. An electrochemical method was used to study online the nerve stimulation-induced rise in the extracellular concentration of endogenous noradrenaline at the probe, a carbon fibre electrode (CF). This parameter, which does not directly represent noradrenaline release, but reflects release minus clearance, has been termed Δ[NA]CF. The effects of a number of pharmacological agents on the EJCs were examined both at 0.1 and 2 Hz, and the effects on the EJC response to 100 pulses at 2 Hz compared with that on the Δ[NA]CF response. Clonidine and xylazine were used as α2-agonists, yohimbine and idazoxan as α2-antagonists and desipramine and cocaine as blockers of noradrenaline reuptake. Most of these agents had unwanted side effects, especially at higher concentrations. However, clonidine and xylazine depressed at lower concentrations the EJC and Δ[NA]CF responses to about the same extent; these effects were partially or completely reversed by yohimbine. Yohimbine or idazoxan did not affect the EJCs at 0.1 Hz but enhanced the EJC and Δ[NA]CF responses to 100 pulses at 2 Hz to the same extent. All effects of desipramine (1 μM) seemed explainable as a result of block of noradrenaline reuptake, while cocaine (10 μM) in addition exerted an ‘unspecific' depressant (probably local anesthetic) effect. Under control conditions, both agents depressed the EJC but dramatically enhanced the Δ[NA]CF response to 100 pulses at 2 Hz. Addition of yohimbine prevented the depressant effect of desipramine on the EJCs completely and reduced that of cocaine, but increased their effects on the Δ[NA]CF response. These results are compatible with the view that ATP and noradrenaline are released in parallel from the sympathetic nerve terminals of this tissue. The different, and under some conditions even opposite, effects of desipramine or cocaine on the EJC and Δ[NA]CF responses are explainable in terms of the known post-secretory effects of these agents. Springer-Verlag, 1992 Rat tail artery nationallicence Co-transmission nationallicence Presynaptic α2-adrenoceptors nationallicence Uptake blockers nationallicence Noradrenaline-ATP nationallicence Msghina M. Department of Physiology, Karolinska Instituter, S-10401, Stockholm, Sweden aut Mermet C. INSERM U171, CNRS UA, Hopital Ste Eugenie, Pav. 4H, F-69230, St Génis Laval, France aut Gonon F. INSERM U171, CNRS UA, Hopital Ste Eugenie, Pav. 4H, F-69230, St Génis Laval, France aut Stjärne L. Department of Physiology, Karolinska Instituter, S-10401, Stockholm, Sweden aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/2(1992-08-01), 173-186 0028-1298 346:2<173 1992 346 210 https://doi.org/10.1007/BF00165299 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00165299 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Msghina M. Department of Physiology, Karolinska Instituter, S-10401, Stockholm, Sweden aut NATIONALLICENCE 700 1- Mermet C. INSERM U171, CNRS UA, Hopital Ste Eugenie, Pav. 4H, F-69230, St Génis Laval, France aut NATIONALLICENCE 700 1- Gonon F. INSERM U171, CNRS UA, Hopital Ste Eugenie, Pav. 4H, F-69230, St Génis Laval, France aut NATIONALLICENCE 700 1- Stjärne L. Department of Physiology, Karolinska Instituter, S-10401, Stockholm, Sweden aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/2(1992-08-01), 173-186 0028-1298 346:2<173 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer