Involvement of Opioid Receptors and Ascorbic Acid in the Improvement of Anxiety-Induced Nicotine in Adult Male Mice

Anxiety is an adaptation response that is created in response to multiple physiological and environmental stresses. It is clear that involvement of various neurotransmitter systems has important role in the anxiety process. Vitamin C is a water-soluble antioxidant that plays a role in many physiological reactions in the body. On the other hand, nicotine, which increases with tobacco intake, has an anxiogenic effect. Naloxone, as an opioid receptor antagonist, also plays an important role in the development of anxiety behavior. The aim of this study was to investigate the role of naloxone-co-administered vitamin C on anxiety induced nicotine.

84 male mice (30 ± 2 gr) were randomly divided into 12 groups. Anxiety test was performed 30 minutes after intraperitoneal injection of drugs by an elevated plus maze apparatus for 5 minutes. Anxiety indices such as percentage of open arm entry (OAE%) and percentage of time staying in the open arm (OAT%) were recorded and evaluated.
Findings: In this research, injection of nicotine (0.8 mg/kg, ip) increased anxiety behaviors. Vitamin C (80 mg/kg, ip) improved the nicotine-induced anxiety. This effect of vitamin C was inhibited by ineffective dose of naloxone (4 mg/kg, ip).

It seems that vitamin C decreases anxiety behavior of nicotine in the presence of opioid receptors.