In a neuronal culture experiment, the effect of a chemical (under study) was prevented by pretreating the cells with prazosin, an alpha1…
In a neuronal culture experiment, the effect of a chemical (under study) was prevented by pretreating the cells with prazosin, an alpha1 adrenoceptor antagonist but not by propranolol, a beta adrenoceptor antagonist. The chemical under study is likely to be:
Select an option to attempt
Correct Answer: Option D
Explanation
Prazosin and propranolol pharmacology — receptor identification:Experimental setup: A chemical causes a physiological response. Prazosin (-adrenoceptor blocker) prevented the effect, but propranolol (-adrenoceptor blocker) did NOT prevent it.Conclusion:• Since prazosin (blocker) blocked the effect, the chemical acts throughadrenoceptors.• The chemical must be anadrenoceptor AGONIST.• Noradrenaline (norepinephrine): primarily anagonist (and someactivity).• Methoxamine: a selectiveadrenoceptor agonist.Both Noradrenaline and Methoxamine act viareceptors, consistent with the experiment.Answer: The chemical acts viaadrenoceptors; both noradrenaline and methoxamine areagonists.