<prompt> Which of the following act on a-2 receptors -RhenylephrineMitodrineClonidineMethoxomine  <response>: Ans. is c i.e., Clonidinea-2 agonistso These are:a Apraclonidine and brimonidine are used in glaucoma.b Dexmedetomidine is used as preanaesthetic medication and for sedation in critically illventilated patient in ICU.c Tizanidine is used as muscle relaxant in spaciticity.d Clonidine and a methyldopa are used in hypertension. Other uses of clonidine are i preanaesthetic medication, ii diarrhea in diabetic neuropathy, iii analgesic, iv withdrawal syndrome of opoid, alcohol and nicotine, v prophylaxis of migrain, vi postmenopausal syndrome, vii suppression test for pheochromocytoma, and viii for treatment of ADHD. 