Effects of NG-nitro-L-arginine methyl ester, 7-nitro indazole, and agmatine on pentylenetetrazol-induced discriminative stimulus in Long-Evans rats.
This study was undertaken to determine any role that nitric oxide (NO) may play in the discriminative stimuli produced by pentylenetetrazol (PTZ). The PTZ-induced discriminative stimulus is pharmacologically similar to anxiety in humans and is used in a behavioral assay of anxiety (the PTZ model of anxiety). In the present study, effects of L-N(G)-nitro arginine methyl ester (L-NAME), 7-nitroindazole (7-NI) and agmatine, NO synthase (NOS) inhibitors, on PTZ-induced discriminative stimulus were investigated in male Long-Evans rats (330-350 g). Rats were trained to discriminate PTZ (16 mg/kg) from saline using a two-lever, food-reinforced choice procedure (FR 10). The rats that met the training criteria were injected with L-NAME (15, 30, and 60 mg/kg), 7-NI (15 and 30 mg/kg), agmatine (20, 40, and 60 mg/kg), and saline or vehicle intraperitoneally before each test. They were tested for the PTZ-discrimination to determine if the NOS inhibitors produce discriminative stimulus similar to PTZ or if they block PTZ-induced discrimination. Treatment with the NOS inhibitory drugs neither substituted for PTZ nor altered the PTZ lever selection in any other way. These findings suggest that PTZ-induced discriminative stimulus may not be related to NO-mediated central mechanisms.
Uzbay
I Tayfun
IT
Psychopharmacology Research Unit, Department of Medical Pharmacology, Gülhane Military Medical Academy, Etlik, Ankara, Turkey. tuzbay@gata.edu.tr
Lal
Harbans
H
D000376:Agmatine / Q000494:pharmacology*; D000818:Animals; D004193:Discrimination Learning / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010433:Pentylenetetrazole / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans
D004791:Enzyme Inhibitors; D007191:Indazoles; D000376:Agmatine; D019001:Nitric Oxide Synthase; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester; D010433:Pentylenetetrazole