Non cholinergic dependent mechanism of Ocimum gratissimum induced neurobehavioural alterations in mice

This study investigated the mechanism of Ocimum gratissimum induced neurobehavioural alterations in mice. The plant is widely consumed in most parts of the world including Nigeria where it is used as a spice and phytomedicine by alternate medical practitioners.

The animals were divided into three groups of six mice each. Control and Ocimum gratissum treated mice were subjected to the hole-board, light/dark box, elevated plus maze and open field tests. The third group had an intraperitoneal (i.p) injection of the cholinergic receptor antagonist, atropine (3 mg/kg) forty-five minutes prior to oral Ocimum gratissimum administration before the neurobehavioural assay one hour later.

The results showed that Ocimum gratissimum administration significantly reduced the number of head dips in the hole board test (p < 0.01), so also were the frequencies of locomotion (p < 0.001), rearing (p < 0.05) and grooming (p < 0.01) compared with control. In the light/dark board test, the time spent in the light arena and the number of entries were significantly (p < 0.001) reduced compared with the control, while in the elevated plus maize test, the time spent in the closed arm increased significantly (p < 0.01) when compared with control values. The values obtained when the animals were pre-treated with atropine (3 mg/kg) before the administration of Ocimum gratissimum showed no significant difference from those observed without the cholinergic blocker in all the four neurobehavioural tests.

These results ruled out any significant participation of the cholinergic system in Ocimum gratissimum induced neurobehavioural alterations in mice.