Altered histamine H3 binding in rat forebrain after reserpine treatment.
Groups of 6 rats were treated for 5 days with either reserpine hydrochloride (5 mg/kg i.p., per diem), or saline. Regional binding of the histamine H3 agonist N alpha-[3H]methyl-histamine ([3H]NAMH) was determined in forebrain sections by quantitative autoradiography and Scatchard analysis. Highest maximal binding was in nucleus accumbens (107 +/- 18 fmol/mg) and corpus striatum (58 +/- 9 fmol/mg), where the apparent affinity was close to 4 nM. Maximal binding of [3H]NAMH in the insular cortex (39 +/- 6 fmol/mg) was higher than in other cortical areas examined. Reserpine treatment produced a 50% decrease in both the Bmax and the apparent Kd in the corpus striatum and nucleus accumbens, but binding parameters in the cortex and septum were unaltered. Therefore, the response of H3 receptors in rat forebrain to reserpine treatment for 5 days was regionally heterogenous such that maximal [3H]NAMH binding was typically higher in insular cortex (36 +/- 6 fmol/mg) than in corpus striatum (24 +/- 3 fmol/mg) of reserpine-treated rats.
Montreal Neurological Institute, McGill University, Que., Canada.
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Cumming
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Vincent
D000818:Animals; D008297:Male; D016548:Prosencephalon / Q000187:drug effects* / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D011968:Receptors, Histamine / Q000187:drug effects* / Q000378:metabolism; D018100:Receptors, Histamine H3; D012110:Reserpine / Q000494:pharmacology*
D011968:Receptors, Histamine; D018100:Receptors, Histamine H3; D012110:Reserpine