Comparison of cortical adrenergic, cholinergic and benzodiazepine receptors between albino rat and desert rat (Mastomys natalensis) using radioreceptor binding

Abstract

Cortical alpha-adrenergic, beta-adrenergic, cholinergic (muscarinic) and benzodiazepine receptors have been studied in the albino rat and Mastomys natalensis (desert rat) using radioligand binding. Scatchard analysis was performed to determine affinity (Kd) and density (Bmax) of receptors. Compared to the albino rat, the desert rat was found to have higher affinity and density of alpha-adrenergic receptors. Beta-adrenergic receptors had similar Kd in both species but Bmax was significantly lower in the desert rat as compared to the albino rat. Cholinergic (muscarinic) receptors as well as the benzodiazepine receptors were in significantly higher density in the desert rat. The affinity was low for muscarinic receptors in the desert rat but equal for benzodiazepine receptors in both species. Since there are more alpha-adrenergic, muscarinic and benzodiazepine receptors in the desert rat, this species should be of value in screening compounds active at these sites.