Effect and function mechanism of Galanin on neonatal rat locus coeruleus neurons / 中国生化药物杂志

ABSTRACT

Objective To explore the effect of galanin ( GAL) on locus coeruleus ( LC) neurons from neonatal rat and mechanism with its receptor GalR and potassium channel.Methods Brain slices from neonatal rats were prepared and the resting membrane potential and spontaneous action potential of LC neurons were recorded with whole cell patch-clamp configuration.GAL, AR-M1896 and potassium channel blockers were bath applied with different concentration.Results Bath application GAL induced hyperpolarization and inhibited firing rate of LC neurons.However, AR-M1896 ( a selective GalR2 agonist) did not induce significant effect on LC neurons, only at very high concentration(1μM) it induced slight hyperpolarization and reduced firing rate.The inhibitory effect of GAL was partially blocked by TEA ( an antagonist of voltage-dependent potassium channel) and significantly blocked by BaCl2(an antagonist of inward-rectifying potassium channels), while other potassium channels blockers such as Glybenclamide(ATP-sensitive potassium channel blocker),Charybdotoxin(large-conductance Ca2 +-activated K + channels blocker),Apamin(small-conductance Ca2 +-activated K +channels blocker) failed to block it.Conclusion GAL inhibits LC neurons from neonatal rats, mainly through GalR1.TEA-sensitive potassium channels and inward-rectifying potassium channels, but not ATP-sensitive potassium channel and calcium-activated potassium channel, are involved in this inhibition.