Is there a third heart beta-adrenoceptor?
A series of partial agonists with high affinity for myocardial beta 1- and beta 2-adrenoceptors cause stimulant effects in heart that are resistant to blockade of beta 1- and beta 2-adrenoceptors. The concentrations of partial agonist that cause stimulant effects greatly exceed those that cause blockade. Alberto Kaumann suggests that such non-conventional partial agonists, often analogues of pindolol, may act through a third heart beta-adrenoceptor, which resembles the beta 3-adrenoceptor of white adipocytes and smooth muscle of airways and ileum.
Kaumann
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D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002415:Cats; D006168:Guinea Pigs; D006801:Humans; D009206:Myocardium / Q000648:ultrastructure*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta