Effect of nicotine on serotonin (5-HT) levels in brain of depressed rats

Abstract

Background: Reduction in brain serotonin (5-HT) levels contributes to depression. Nicotine may have antidepressant properties and smokers self-medicate underlying depression. Epidemiological findings suggest that smokers more often demonstrate depressive symptoms than non-smokers and depressed patients are less likely to cease smoking. Therefore, the study was planned to evaluate the effect of nicotine on serotonin levels in brain of depressed rats.Methods: Antidepressant action of study drugs was evaluated using isolation induced hyperactivity model in rats. Rats were divided into five groups with six rats in each group. Study groups: Vehicle in normal rats 1 ml/kg (subcutaneous); vehicle after isolation 1ml/kg (subcutaneous); imipramine 10 mg/kg (intraperitoneal) for 7 consecutive days; single dose of nicotine 0.4 mg/kg (subcutaneous); single dose of nicotine 0.2 mg/kg (inhalational). Brain serotonin assay was carried out. The statistical significance was determined by ANOVA followed by Tukey test (p<0.05).Results: Serotonin levels (55.93ng/g of brain tissue) in rats after isolation were significantly less than in normal rats (335.87ng/g) (p<0.001). In imipramine treated group, serotonin levels (301.4ng/g) after isolation were highly significant as compared to serotonin levels in vehicle treated group after isolation (p<0.001). Nicotine administered by subcutaneous and inhalational route showed significantly higher brain serotonin levels, i.e. 175ng/g and 254.62ng/g respectively as compared to vehicle treated rats after isolation (p<0.001).Conclusions: Single dose nicotine (inhalational) produced significant antidepressant action comparable to that of seven days’ treatment of standard antidepressant drug imipramine in rats. In rats, nicotine by both routes i.e. subcutaneous and inhalational increased serotonergic activity.

Parkinsonian phenotypes induced by Synphilin-1 expression are differentially contributed by serotonergic and dopaminergic circuits and suppressed by nicotine treatment

“…Our study advances this issue by showing that serotonergic and dopaminergic systems influence the detection of PD-associated symptoms in flies. Moreover, our data support that nicotine or a molecule with similar pharmacological properties may be a suitable treatment for some of these symptoms, as nicotine is known to increase the amount of available serotonin in the brain [29].…”

l-Arginine attenuates the ethylene glycol induced urolithiasis in ininephrectomized hypertensive rats: role of KIM-1, NGAL, and NOs

“…NO is an important signaling molecule involved in neurotransmission, vasodilatation, immune regulation, and host defense. [23][24][25] L-Arginine has been reported to have many biologically important properties including antiatherosclerotic, wound healing, gastro-protective, 26 and platelet aggregation inhibitory potential. 27 It is also known to have ameliorative effects against inflammatory bowel diseases, 28 intestinal ischemia-reperfusion injury, 29 and liver ischemiareperfusion injury.…”

In-vitro Free Radicals Scavenging and Antioxidant Activity of Rice Bran Extract

“…Oxygen free radicals and nitrogen free radicals are generated within the cells due to the various metabolic processes and mitochondrial energy production [1][2][3][4][5] . These radicals are responsible for beneficial as well as deleterious response.…”