Morphine and clonidine activate different K+ channels on rat amygdala neurons.
In cell-attached patch-clamp recordings from freshly dissociated neurons of the rat amygdalohippocampal area, clonidine principally activated a 95-pS (picosiemens) inwardly rectifying K+-permeable channel, whereas morphine acting at mu-opioid receptors activated a different 130-pS channel. Clonidine's effects were largely antagonized by the alpha(2)-adrenoceptor antagonist idazoxan, but were poorly mimicked by agmatine. These results partially contradict the prevailing hypothesis that alpha(2) and opioid receptors act through the same ion channel transduction pathways.
Murphy
R
R
Department of Pharmaceutical Sciences, Northeastern University, 211 Mugar Building, 360 Huntington Avenue, Boston, MA 02115, USA.
Freedman
J E
JE
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000679:Amygdala / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D019329:Idazoxan / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats
D000317:Adrenergic alpha-Antagonists; D000700:Analgesics; D015221:Potassium Channels; D009020:Morphine; D003000:Clonidine; D019329:Idazoxan