A child, Ramu has swallowed the contents of 2 bottles of a nasal decongestant whose primary ingredient is a adrenoceptor agonist drug. The signs of a activation that may occur in this patient include :: (A) Tachycardia, (B) Dilatation of pupil, (C) Vasodilation, (D) All of the above
Answer is B. a-receptors are present on the radial muscles of the iris. Stimulation of a-receptors cause contraction of the radial muscles and will cause mydriasis Whereas tachycardia and vasodilation are due to activation of b-adrenergic receptors.