title: Effects of imidazoline I2 receptor ligands on acute nociception in rats.
abstract: This study examined the antinociceptive effects of seven imidazoline I2 receptor ligands in a rat warm water tail withdrawal procedure (46 and 50 °C). Agmatine, 2-BFI, phenyzoline, and diphenyzoline produced a significant antinociceptive activity at 46 °C. BU224, S22687, and idazoxan had no effect at 46 °C up to doses that altered the locomotor activity. None of the drugs showed antinociceptive activity at 50 °C. It is suggested that I2 receptor agonists have antinociceptive activity for acute phasic pain under weak noxious stimulus, and the effects are efficacy-dependent. These data explain the findings that I2 receptor agonists enhance the antinociceptive effects of opioids and support developing higher-efficacy I2 receptor agonists for the treatment of pain.
authors: Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214-3000, USA.
authors: Cristal
authors: C
authors: Sampson
authors: Yanan
authors: Y
authors: Zhang
authors: Fabio
authors: F
authors: Del Bello
authors: Jun-Xu
authors: JX
authors: Li
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D054755:Imidazoline Receptors / Q000819:agonists*; D008024:Ligands; D008297:Male; D010146:Pain / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D054755:Imidazoline Receptors; D008024:Ligands; C487767:imidazoline receptor 2