Cerebral concussion in rats rapidly induces hypothalamic-specific effects on opiate and cholinergic receptors.
Conscious male adult rats were concussed by a blow to the occiput with a blunt dart, shot from a spring-loaded pistol. Animals were decapitated within 2 sec, brains quickly removed, several brain regions homogenized in cold buffer and radioreceptor assays carried out. There was a 20% increase in binding of [3H]naloxone and [3H]QNB in the hypothalamus but not in the amygdala, striatum, hippocampus, cortex, midbrain and hindbrain. For animals killed 5-10 sec after concussion, when normal conscious behavior had returned, there were no changes in binding between control and concussed rats. Binding of [3H]spiroperidol and [3H]ouabain was unaffected by concussion. To rule out changes due to non-specific stress, one series of rats received a blow to the lower body. There was no change from control in [3H]QNB binding to hypothalamic tissues by a body blow as compared with the blow to the head. The findings suggests decreased binding of endogenous endorphins and acetylcholine to their respective receptors as a result of concussion. The transient deficit in endogenous transmitter binding may temporarily interrupt hypothalamic circuits concerned with the state of consciousness.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D001924:Brain Concussion / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D009270:Naloxone / Q000378:metabolism; D009928:Organ Specificity; D010042:Ouabain / Q000378:metabolism; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism
D011950:Receptors, Cholinergic; D011957:Receptors, Opioid; D009270:Naloxone; D013134:Spiperone; D010042:Ouabain; D011813:Quinuclidinyl Benzilate