EEG effects of microinjection of naloxone in the region of the nucleus tractus solitarius of the rat.
In recent years, we have carried out several studies on brainstem mechanisms associated with pain modulation. Of particular interest has been the region of the nucleus tractus solitarius (NTS) at the level of the area postrema (AP) in the dorsomedial medulla. This region has been found to be rich in opiate receptors and to be involved in pain modulation. Having previously demonstrated the EEG and behavioral effects of systemic administration of morphine, we initiated the present study to determine whether microinjection of naloxone directly into the region of the NTS will modify any or all of the EEG effects induced by subsequent systemic administration of morphine. Our results have shown that microinjections of naloxone into the region of the NTS block the cortical EEG synchronizing effects of systemically administered morphine. These results indicate that morphine-induced cortical EEG synchronization is mediated through the region of the NTS. This region may, therefore, comprise part of an opiate sensitive system which can influence cortical EEG activity.
D000818:Animals; D004569:Electroencephalography; D007276:Injections, Intraventricular; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D009270:Naloxone; D009020:Morphine