ABSTRACT
BACKGROUND: Nicotine is a subject of continuous research because of its likely ameliorative effects on neurologic and neurodegenerative disorders. PURPOSE: This study examined the effects of its chronic subcutaneous administration on hippocampal and striatal microstructure in both female and male rats. METHODS: Forty adult female and male Wistar rats were divided into 4 groups. Three experimental groups were administered nicotine via subcutaneous injections at doses of 0.25, 2 and 4 mg/kg body weight for 28 days. Control groups received normal saline. Following administration, routine processing of brain tissues was carried out. Sections obtained were stained using routine H&E methods for general histological appearance, Cresyl violet methods for nissl substances, and Bielschwolsky silver impregnation method for neuritic plaques and neurofibrillary tangles. RESULTS: The study showed significant increase in percentage of neurons showing degenerating features in the hippocampus and striatum of both female and male rats following the higher doses of nicotine treatment. Only female rats showed positive agyrophilic (black-coloured) aggregations in the hippocampal and striatal regions after nicotine treatment. CONCLUSION: The present study indicates that higher dose of chronic nicotine administration may induce hippocampal and striatal neurodegenerative changes. However, further studies using more specific method for studying neurodegeneration within brain regions is recommended.
ABSTRACT
BACKGROUND: Nicotine has shown potential therapeutic value for neurodegenerative diseases though there are concerns that it may induce behavioural deficits. PURPOSE: The present study sought to determine the effect of chronic nicotine administration on overall motor functions and coordination. METHODS: Forty adult female and male Wistar rats were randomly grouped into 4 groups. Treated groups were administered nicotine via subcutaneous injections at doses of 0.25, 2 and 4 mg/kg body weight for 28 days. Control groups received normal saline. All animals were monitored for the first few minutes after each injection for any observed immediate effect of drug administration. Motor associated behavioural tests performed include: open field test, string test for grip strength and limb impairment, movement initiation and step test. RESULTS: Nicotine induced muscular convulsions within the first 1-5 minutes following daily subcutaneous injections, throughout the period of administration. This was observed to be more severe in females. Nicotine did not produce major alterations in overall motor functions and coordination in both females and males. CONCLUSION: The present study shows chronic nicotine treatment produces muscular convulsion but no major deficit in overall motor function and coordination and that any observed alterations may just be transient effects.
ABSTRACT
BACKGROUND: Antiepileptic drugs used to avert epileptic seizures necessitate prolonged duration for improved efficacy and could induce some side effects. PURPOSE: The present study investigated the effect of chronic administration of two common antiepileptic drugs - gabapentin and carbamazepine, on the histomorphology of the hippocampus and striatum in adult rats. METHODS: 25 adult male Wistar rats were grouped randomly into 5 groups. 3 groups were administered either therapeutic doses of gabapentin (16 mg/kg) or carbamazepine (20 mg/kg) or sub-therapeutic dose of gabapentin plus carbamazepine (8 + 10 mg/kg). To confirm anticonvulsant effects, these animals were kindled for seizures at sub-maximal electroshock. Appropriate negative and positive controls were given normal saline. At the end of treatment, brain tissues were obtained and processed for histological procedures. RESULTS: The study confirm significant decrease (P<0.001) in convulsion parameters tonic flexion, tonic extension and clonic convulsion, between drug treated groups and electroshock control. Histological studies revealed significant increase (p<0.001) in neurons showing features of degeneration in the hippocampus, for drug treated groups as compared to normal and electroshock control. Also, drug treatment reduced nissl activity in both hippocampus and striatum. CONCLUSION: Chronic administration of gabapentin and carbamazepine may cause increase in neurodegenerative changes in the adult brain.
