A comparative study of the effects of intraperitoneal and intracerebral ventricle injections of muscimol on blood glucose regulation in mice

A bilateral relationship between GABA, an inhibitory neurotransmitter in the CNS, and hormones that regulate blood glucose has been reported. There are some reports that GABA via increasing Insulin plasma and decreasing Glucagon and somatostatine cause a decrease in blood glucose levels. To investigate the role of muscimol (GABA-A receptor Agonist) in this experimental study, male Albino mice (20-30 gram) were used. To measure blood glucose at specified intervals, serial blood collection from each animal was done by retro-orbital sinus puncture and glucose concentration was measured using -toluidin by spectrophotometer. For IP and ICV injections of muscimol 10 groups of mice were selected (5 for IP, 5 for ICV). Each of these groups received a different dose of muscimol. Immediately after every injection of musimol, a blood sample was taken, and this procedure was repeated every 30 minutes for 180 minutes. One-way ANOVA and Post Hoc were used to compare the results. The results indicated that intraperitoneal (IP) injection of 1,2,4 mg/kg doses of muscimol not only did not reduce blood glucose in the experimental group but with increase of the muscimol dose up to 6 mg/kg significantly increased blood glucose. The results however, also indicate that ICV injection of muscimol significantly reduces the blood glucose concentration (p<0.05). On the whole, it seems that in ICV injection, it is muscimol itself that affects blood glucose, while in IP injection it is metabolized, the metabolites resulting in the increased blood glucose. In other words effects of IP and ICV injection of muscimol differ. Since the effects of GABA-A receptors on blood glucose concentration are a complex phenomenon, further research seems vital.