<prompt> Which of the following term best describes the antagonism of bronchoconstrictor effect mediated at the leukotriene receptorsof leukotrienes by terbutaline acting at the adrenoceptors in a patient with asthma?Pharmacologic antagonistPartial agonistPhysiologic antagonistChemical antagonist  <response>: Physiological functional antagonismThe two drugs act on different receptors or by different mechanisms, but have opposite overt effects on the same physiological function. i.e. have pharmacological effects in opposite direction, e.g.Histamine and adrenaline on bronchial muscles and on BP.Hydrochlorothiazide and amiloride on urinary K excretion.Glucagon and insulin on blood sugar level.Key Concept: Drugs producing opposite action by acting on different receptors are called physiological antagonists.Reference: Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI page no 68 