Anaes SAQs · Applied cardiovascular & respiratory physiology
Pharmacodynamics — receptors and the dose-response relationship
Primary — affinity (Kd/pA2), efficacy (Emax), potency (EC50); graded vs quantal curves; competitive (rightward parallel shift, Emax preserved, pA2) vs irreversible (lower Emax) antagonism; partial agonist (intrinsic activity less than 1, acts as competitive antagonist in presence of full agonist — buprenorphine, aripiprazole); biased agonism (G-protein-biased mu-opioid, carvedilol).
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Prompt
Define affinity, efficacy and potency, and distinguish a competitive from an irreversible antagonist using the dose-response curve. Explain how a partial agonist can behave as an antagonist, and outline the concept of biased agonism with an anaesthetic example.
Question
Define affinity, efficacy and potency, and distinguish a competitive from an irreversible antagonist using the dose-response curve. Explain how a partial agonist can behave as an antagonist, and outline the concept of biased agonism with an anaesthetic example.
References6ShowHide
- [1]Pence A, et al. Competitive interactions between propofol and diazepam at GABA(A) receptors. J Pharmacol Exp Ther, 2022.PMID 36167415
- [4]Zhang Y, et al. Autonomic modulation by a G protein-biased mu-opioid receptor agonist. PLoS One, 2026.PMID 42139241
- [5]Ji RL, et al. Biosensors for translatable GPCR bias. Trends Pharmacol Sci, 2026.PMID 42285785
- [6]Hamed O, et al. The β-Blocker Carvedilol and Related Aryloxypropanolamines Promote ERK1/2 Phosphorylation in HEK293 Cells with K (A) Values Distinct From Their Equilibrium Dissociation Constants as β (2)-Adrenoceptor Antagonists: Evidence for Functional Affinity. J Pharmacol Exp Ther, 2024.PMID 38129128
- [7]Edelstein GA, et al. Dopamine antagonist effects of the D2/D3 receptor partial agonist aripiprazole on effort-based choice tasks in male and female rats. Cogn Affect Behav Neurosci, 2026.PMID 40993487
- [42285786]Bersten AD, Soni N (eds) Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.