Adrenoceptor sensitivity in disease as assessed through response to temperature alteration

Drug receptors are usually defined in terms of specific agonists and blocking agents. The adrenoreceptor occurs in two forms, alpha and beta. From a pharmacologic point of view, this receptor concept has proved useful by allowing the development of new, selective agonists and blocking agents. From a physiologic viewpoint, there is no need for two receptors. Clinically, it is important to find out whether the pharmacologic adrenoceptors are immutable. Evidence is accumulating, both pro and con, regarding this point. Some of the effects of temperature on the response of the isolated dilator muscle of the rabbit iris to catecholamines are described. The following questions are asked: Is it not possible that there is only one adrenoceptor whose specific agonists are epinephrine or norepinephrine? Do the alpha and beta configuration depend only on the local environment? While no answers are given, it is concluded that these are clinically relavant questions.