Morphine increases locus coeruleus noradrenergic neuronal activity in vitro.
Morphine produced a dose-dependent increase in the activity of norepinephrine-containing locus coeruleus neurons recorded from mouse brain slices in vitro. The response was not changed in a low calcium-high magnesium incubation medium, indicating that the observed effects are the result of a direct action of morphine on locus coeruleus neurons. When the mice were anesthetized with chloral hydrate prior to preparation of tissue slices, morphine produced a dose-dependent suppression of noradrenergic neuronal activity. These studies suggest that previous data showing a decrease in activity of locus coeruleus neurons following incubation with morphine in vitro are due to the use of anesthesia.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D008125:Locus Coeruleus / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000502:physiology*
D009020:Morphine; D008274:Magnesium; D002118:Calcium; D009638:Norepinephrine