[Dynamic changes of myocardial beta, alpha 1-adrenergic and muscarinic cholinergic receptors in endotoxic rats].
The dynamic changes of myocardial beta, alpha 1-adrenergic and muscarinic cholinergic receptors (beta AR, alpha 1AR, MAchR) were investigated in endotoxic rats by radiolabelled ligand binding assay. It was found that the number of beta AR increased, while its affinity decreased progressively following endotoxin injection. The number of alpha 1AR reduced significantly during the whole course of the experiment but no change was found in its affinity. The affinity of MAchR was not changed and the number of MAchR reduced only at agonal stage. The up regulation of beta AR in early stage might indicate a compensatory mechanism, while the attenuation in affinity of beta AR and/or the number of alpha 1AR might result in the decreased responsiveness of heart to catecholamine stimulation. Since the affinity of beta AR reduced prominently at the agonal stage, the up regulation of beta AR seemed to be discompensated. The down regulation of MAchR at agonal stage of endotoxic rats might share some light of its compensatory action to the discompromised relationship between the adrenergic and cholinergic system sbut it seemed to be with no effect, which might correlate with myocardial failure.
Bao
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Y
D000818:Animals; D015536:Down-Regulation; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012772:Shock, Septic / Q000378:metabolism*; D015854:Up-Regulation
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic