Abstracts

Fatty acids exert important modulatory effects on cellular excitability and receptor-mediated signalling pathways. Polyunsaturated fatty acids can modify neuron firing, neurotransmitter release and neuronal ionic currents. Linolenic acid (LA) is a omega 3 polyunsaturated fatty acid. The aim of the study was to evaluate the anticonvulsive effect of daily supplementation with LA as compared to the ketogenic diet 4 week-old male Wistar rats were fed one of the following diets for 30 days: ketogenic diet (KD, n = 9), regular diet (Sham, n = 14), regular diet with daily palm oil supplementation (PO, C16:0, n = 10) or regular diet with daily LA supplementation (LA, C18:3w3, n = 12). Pentylenetetrazol threshold (PTZth) was used to assess the anticonvulsive effects of the diets. PTZ was dissolved to obtain a concentration of 10mg/kg and was infused into the tail-vain at the rate of 2ml/h. The dose used to obtain the seizure threshold (mg/kg) was derived from the time required to obtain the first bilateral forelimb myoclonus. Nutritional status was monitored by body composition evaluation using dual-energy X-ray absorptiometry (Lunar PIXImus densitometer) at the beginning of the dietary modifications and after the PTZth testing Following 30 days with their respective diets, the PTZth (mean[plusmn]sem) were 43.2[plusmn]1.9 mg/kg in Sham group, 51.2[plusmn]1.8 mg/kg in KD group, 47[plusmn]2.3 mg/kg in PO group and 52.1[plusmn]2.3 mg/kg in LA group (p=0.003). LA was found to be significantly different from the Sham (p=0.006), but not from the KD (p=0.86). KD was found to be significantly different from the Sham (p=0.005), and PO was not different to Sham (p=0.17) and KD (p=0.113) groups. With respect to the nutritional status, the fat mass did not differ among group at inclusion (p=0.328) and after PTZth (p=0.06). Fat masses (% of total body weight) were at inclusion (mean[plusmn]sem) 12.4[plusmn]0.3 % in Sham group, 12.1[plusmn]0.2 % in KD group, 11.7[plusmn]0.3 in PO group and 12.3[plusmn]0.2 in LA group and were : 16.1[plusmn]0.6, 19,3[plusmn]1.2, 17.6[plusmn]0.7 and 16.8[plusmn]0.7, respectively, after PTZth Daily oral supplementation in rats with LA is as effective as KD using PTZ threshold as a test for anticonvulsive activity. There is no evidence that PO oral supplementation (saturated fatty acid) supports anticonvulsive activity. It was described that LA had anticonvulsive and neuroprotective proprieties using intravenous pre-treatment conditioning. Lipids are an important constituent of the neuronal membrane and can modify membrane composition, fluidity and/or lipid-dependant cell metabolism. Due to the high amount of fatty acids in the ketogenic diet, we suggest that similar underlying mechanisms may support all or part of the anticonvulsive mechanisms in both KD and LA supplementation. Further exploration is required to explain the anticonvulsive activity of LA (Supported by AEAC association.)