alpha2-Adrenoceptor-mediated potassium currents in acutely dissociated rat locus coeruleus neurones.

J. Arima, Chiharu Kubo, H. Ishibashi, N. Akaike

Research output: Contribution to journalArticle

Abstract

1. The noradrenaline (NA)-activated response was investigated in neurones acutely dissociated from the rat locus coeruleus (LC) using nystatin-perforated, conventional whole-cell and inside-out patch recording modes under current- and voltage-clamp conditions. 2. Under current-clamp conditions, NA hyperpolarized the LC neurones, abolishing the spontaneous action potentials. In voltage-clamp studies, NA induced an inwardly rectifying K+ current (INA) in a concentration-dependent manner with a half-maximum effective concentration of 2.2 x 10(-7) M. 3. INA was mimicked by the alpha2-agonist UK14304 but was inhibited by either the alpha2B/alpha2C antagonist ARC239 or the alpha1- and alpha2B/alpha2C antagonist prazosin, suggesting the contribution of alpha2B/alpha2C adrenoceptors. 4. INA was inhibited by the intracellular application of GDPbetaS but fully activated by intracellular perfusion of GTPgammaS. 5. In the inside-out recording mode, the application of GTP to the cytoplasmic side of the patch membrane markedly enhanced the open probability of the NA-activated single channels which represented the inwardly rectifying properties. 6. These results indicate that the activation of alpha2B/alpha2C adrenoceptors coupled with GTP-binding protein directly activates the inwardly rectifying K+ currents in rat LC neurones, thus resulting in a decrease in the spontaneous firing activities.

Original languageEnglish
JournalThe Journal of Physiology
Volume508
Publication statusPublished - Apr 1 1998

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Locus Coeruleus
Adrenergic Receptors
Norepinephrine
Potassium
Neurons
Guanosine 5'-O-(3-Thiotriphosphate)
Nystatin
Prazosin
Guanosine Triphosphate
GTP-Binding Proteins
Action Potentials
Perfusion
Membranes

All Science Journal Classification (ASJC) codes

  • Physiology

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alpha2-Adrenoceptor-mediated potassium currents in acutely dissociated rat locus coeruleus neurones. / Arima, J.; Kubo, Chiharu; Ishibashi, H.; Akaike, N.

In: The Journal of Physiology, Vol. 508, 01.04.1998.

Research output: Contribution to journalArticle

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