What question did this study set out to answer?

To characterize the functional properties of catecholamine-sensitive adenylate cyclase and identify the beta-adrenoceptor subtypes present in human right atrial membranes.

November 1, 1984Journal of Cardiovascular Pharmacology

Human Cardiac β-Adrenoceptors

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Authors

OBOtto‐Erich BroddeHalle Institute for Economic Research NONaoki OʼHaraEssen University Hospital HZHans‐Reinhard ZerkowskiUniversity of Bern

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Implication

In vitro study demonstrates functional coupling of beta-1 and beta-2 adrenoceptors to adenylate cyclase in human atria, highlighting dual-receptor regulation of cardiac signaling.

Key Points

To characterize the functional properties of catecholamine-sensitive adenylate cyclase and identify the beta-adrenoceptor subtypes present in human right atrial membranes.
Prepared cell membrane preparations from human right atria.
Measured adenylate cyclase activity following stimulation with magnesium ions, guanyl nucleotides [Gpp(NH)p, GTP], and catecholamines.
Evaluated subtype selectivity using selective agonists (dobutamine, fenoterol, procaterol) and antagonists (ICI 118,551, betaxolol).
Catecholamine potency followed the rank order (-)-isoprenaline > (-)-adrenaline = (-)-noradrenaline > phenylephrine, indicating beta-1 adrenoceptor predominance.
Dobutamine (beta-1) and procaterol or fenoterol (beta-2) acted as partial agonists with intrinsic activities of 0.5–0.7 relative to isoprenaline (1.0), while combining dobutamine (100 µM) and procaterol (10 µM) fully matched the maximal activation of 10 µM isoprenaline.
Antagonist assays confirmed dual subtype coupling, as the beta-2 antagonist ICI 118,551 selectively inhibited procaterol-stimulated activity, whereas the beta-1 antagonist betaxolol preferentially inhibited isoprenaline-stimulated activity.

Cite This Study

Brodde et al. (1984) studied this question.

synapsesocial.com/papers/6a8bd825bc51310b2bdec9a0 https://doi.org/10.1097/00005344-198406060-00028

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Implication

In vitro study demonstrates functional coupling of beta-1 and beta-2 adrenoceptors to adenylate cyclase in human atria, highlighting dual-receptor regulation of cardiac signaling.

Human Cardiac β-Adrenoceptors

Discussion

Member takes

Implication

Key Points

Cite This Study

Human Cardiac β-Adrenoceptors

Discussion

Member takes

Implication

Key Points

Cite This Study

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