title: A strong influence of serotonin axons on beta-adrenergic receptors in rat brain.
abstract: The role of serotonin axons in modulating the norepinephrine neurotransmission system in rat brain was investigated. Selective lesions of the forebrain serotonergic system were made by injecting 5,7-dihydroxytryptamine into the midbrain raphe nuclei. Four to six weeks after the lesion, the uptake of 3H-labeled serotonin in the frontal cortex and the hippocampus was reduced by more than 90 percent, while neither the uptake of 3H-labeled norepinephrine nor the content of norepinephrine was affected in either tissue. The number of beta-adrenergic receptors, as measured by radioligand binding with 3H-labeled dihydroalprenolol, was increased in the frontal cortex and hippocampus of rats with lesions. Similarly, specific lesions of central serotonin axons produced by systemically administered p-chloramphetamine resulted in an increase in the binding of 3H-labeled dihydroalprenolol to beta-adrenergic receptors and in the production of adenosine 3',5'-monophosphate in response to isoproterenol. These results indicate that serotonin axons may regulate beta-adrenergic receptor number and function in brain.
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D002540:Cerebral Cortex / Q000378:metabolism*; D003000:Clonidine / Q000031:analogs & derivatives / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012701:Serotonin / Q000502:physiology*
chemical_list: D011943:Receptors, Adrenergic, beta; D012701:Serotonin; D004082:Dihydroalprenolol; C016986:apraclonidine; D003000:Clonidine; D009638:Norepinephrine; D011224:Prazosin