A possible receptor role of the subfornical organ in morphine‐induced hyperglycemia

Abstract

Two types of experiments were performed in chronic unanesthetized cats to test the postulate that the subfornical organ serves as a receptor site for morphine-induced hyperglycemia. Morphine was more effective in eliciting hyperglycemia when injected into the third ventricle than into the lateral ventricle. Extent of damage to the subfornical organ produced by intraventricular injection of ethanol appeared to correlate with reduced effectiveness of intraventricular morphine. The hyperglycemic response to intravenous morphine, by contrast, was not diminished in cats whose subfornical organ was damaged by the treatment with ethanol. It is concluded that the subfornical organ may be concerned in the mediation of morphine-induced hyperglycemia, at least in response to intraventricular injection of the drug.