Opiates inhibit pedunculopontine neurones in guinea pig brainstem slices
|Published in||Neuroscience Letters. 1990, vol. 119, no. 1, p. 125-128|
|Abstract||Intracellular recordings were obtained from pedunculopontine neurones in guinea-pig brainstem slices. These cells were characterized by a broad action potential, an A-like conductance and fired spontaneously in a regular manner. These neurones were inhibited by bath-application of both carbachol and serotonine at concentrations of 10(-4) M. Opioid peptides induced a dose-dependent hyperpolarization and a reduction in the spontaneous firing. These latter effects could be blocked by the opiate antagonist naloxone and were direct as they persisted in presence of tetrodotoxine or high magnesium/low calcium-containing salines. They were mediated by an opiate receptor of the mu type since they were obtained with the mu-preferring enkephalin analogues FK 33-824 and DAGO, but neither with the delta nor the kappa analogues such as DPLPE or U-50,488.|
|Keywords||Animals — Brain Stem/cytology/ drug effects/physiology — D-Ala(2),MePhe(4),Met(0)-ol-enkephalin/pharmacology — Dose-Response Relationship, Drug — Electrophysiology — Enkephalin, Ala(2)-MePhe(4)-Gly(5)- — Enkephalins/pharmacology — Guinea Pigs — Narcotics/ pharmacology — Neural Inhibition — Neurons/ drug effects/physiology — Pons/cytology/ drug effects/physiology|
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