Clonidine mydriasis in the rat

European Journal of Pharmacology
T Gherezghiher, M C Koss


Pupillary responses to clonidine (3--100 micrograms/kg, i.v.) and epinephrine (1--30 micrograms/kg, i.v.) were observed in anesthetized rats. Clonidine caused a dose-dependent mydriasis which was effectively antagonized by pretreatment with yohimbine (1.5 mg/kg, i.v.). Pretreatment with phentolamine (5 mg/kg, i.v.) was less effective in antagonizing this clonidine-induced mydriasis. Phenoxybenzamine (2 mg/kg, i.v.) was almost without effect. In contrast, both phentolamine and phenoxybenzamine blocked the pupillary dilation produced by epinephrine while yohimbine pretreatment resulted in no antagonism of epinephrine-induced mydriasis. These results suggest that clonidine-induced mydriasis in the rat is mediated by a central adrenergic inhibitory mechanism.


May 1, 1979·European Journal of Pharmacology·M C Koss
May 28, 1979·Naunyn-Schmiedeberg's Archives of Pharmacology·M C Koss, H D Christensen
Apr 1, 1965·The Journal of Pharmacy and Pharmacology· VAN ROSSUMJ


Jul 1, 1982·Naunyn-Schmiedeberg's Archives of Pharmacology·T GherezghiherM C Koss
Jul 1, 1981·Naunyn-Schmiedeberg's Archives of Pharmacology·H C InnemeeP A van Zwieten
Nov 1, 1980·Naunyn-Schmiedeberg's Archives of Pharmacology·M C Koss
Jan 1, 1985·Naunyn-Schmiedeberg's Archives of Pharmacology·J A HeyM C Koss
Sep 24, 1981·European Journal of Pharmacology·M C Koss
Feb 21, 1994·European Journal of Pharmacology·G HorváthG Benedek
Feb 1, 1995·Pharmacology, Biochemistry, and Behavior·D J HealW R Buckett
Mar 1, 1984·Journal of the Autonomic Nervous System·M C KossA Nomura
Jan 1, 1985·Journal of Ocular Pharmacology·D L Murray, I H Leopold
Feb 3, 2005·Journal of Ocular Pharmacology and Therapeutics : the Official Journal of the Association for Ocular Pharmacology and Therapeutics·Yongxin Yu, M C Koss
Dec 29, 2004·Autonomic Neuroscience : Basic & Clinical·Yongxin Yu, M C Koss
Jul 1, 1982·British Journal of Clinical Pharmacology·J M CliffordJ M Orwin
Jan 1, 1989·British Journal of Pharmacology·J A HeyM C Koss
Jul 1, 1988·British Journal of Pharmacology·J A HeyM C Koss
Jun 8, 2013·Pharmacological Reports : PR·Joanna Raczak-GutknechtRoman Kaliszan
Jan 29, 1982·Documenta Ophthalmologica. Advances in Ophthalmology·H C InnemeeP A van Zwieten

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