Iranian Journal of Physiology and Pharmacology IranJPP 1 (2), 87‐93 Summer 2015 [ArƟcle in Persian] 87 87 ﺗﺄﺳﻴﺲ١٣۴٧ The effect of intracerebroventricular injection of L-arginine on relative expression of mRNA of glutamic acid decarboxylase 1 and 2 (GAD 1 and GAD 2 ) genes in brain stem of neonatal chicken Kasra Mokhtarpouriani 1 , Morteza Zendehdel* 1 , Hossein Jonaidi 2 , Parviz Shayan 3 , Vahab Babapour 1 , Seyedeh Sana Razavi Fard 1 1 Section of Physiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran 2 Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran 3 Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Accepted: 24 August 2015 Received: 1 June 2015 Abstract Introduction: Central Nitrergic and GABAergic play several roles in central nervous system. Release and modulation of some neurotransmitters can be affected by nitric oxide. This study was performed to find the effect of intracerebroventricular (ICV) injection of L-arginine as a donor of nitric oxide on the relative mRNA expression of GAD 1 and GAD 2 in the brain stem of neonatal chicken. Methods: 15 Leghorn neonatal chicks were divided into a control group (no injection), sham group (ICV injection of Evans-Blue 0.1%) and test group (ICV injection of 800 nM L-arginine. Results: ICV injection of L-arginine significantly decreased the relative mRNA expression of GAD 1 and GAD 2 (p<0.05). The relative mRNA expression of these two genes in sham group and control group was similar (p>0.05). Conclusion: It seems that the effect of nitric oxide on GABAergic system in some physiological behaviors such as food intake, is mediated by diminishing of the relative mRNA expression of GAD 1 and GAD 2 . Keywords: L-arginine, GAD 1 , GAD 2 , ICV, Neonatal chicken *Corresponding author e-mail: zendedel@ut.ac.ir Available online at: http://ijpp.phypha.ir E-mail: ijpp@phypha.ir