Agmatine produces antinociception in tonic pain in mice.
Agmatine is an endogenous polyamine metabolite formed by decarboxylation of L-arginine. In this study, the effect of agmatine on tonic pain was compared to its effect on phasic pain by using the formalin and tail-flick (TF) tests in mice. When administered intraperitoneally (ip), agmatine (37.5-300 mg/kg) exhibited a decrease in nociceptive behaviours in the first and second phase of the formalin test, which is a tonic pain model. The alpha(2) adrenoceptor antagonist yohimbine blocked the effect of agmatine in Phase 2 but did not change its effect in Phase 1. In the TF test, there was no significant change in the behaviour of agmatine-administered (75-300 mg/kg) animals. As a result, agmatine appears to have an analgesic effect on tonic rather than phasic pain, and alpha(2) receptors seem partly to have a role in the antinociceptive effect of agmatine on tonic pain.
Onal
A
A
Department of Pharmacology, Faculty of Medicine, Ege University, 35100, Izmir, Turkey. aytul@med.ege.edu.tr
Soykan
N
N
D000376:Agmatine / Q000008:administration & dosage / Q000494:pharmacology*; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D005557:Formaldehyde; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D010147:Pain Measurement / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects
D000700:Analgesics; D018341:Receptors, Adrenergic, alpha-2; D005557:Formaldehyde; D000376:Agmatine