The effect of fish oil on the basal left ventricular function and changes of left ventricular function induced by isoproterenol(ISO)were demonstrated in our study. The detennina-tion of cardiac perfonnance in vivo showed that supplementation with fish oil(EPA and DHA,70%,1.4 ml / kg) had no significant effect on basal cardiac perfonnance,while it could significantly inhibit changes of+ dp / dt_(max),V_(pm) and HR induced by ISO(0.4μg/ kg,4.0μg/ kg,40μg/ kg)intrave-nously.The results suggested that supplementation with fish oil perhaps affected the function of β-adrenoceptors on rat myocardial membrane.
Effects of fish oil on β-adrenoceptors as well as the activity of adenylate cyclase (AC) on rat myocardial membrane were investigated.Supplementation with fish oil had no significant effect on basal activity of AC on myocardial membrane whereas it could markedly inhibit the AC activity stimulated by isoproterenol (ISO). Radioligand binding assays showed that supplementation with fish oil had no effect on Bmax and Kd, compared with saline control. However, supplementation with sheep oil could markedly reduce both the Kd and Bmax, compared with saline control. And the Kd of sheep oil group was greatly decreased than that of fish oil group. The results suggested that supplementation with fish oil mainly affected the activation of AC, not β-adrenoceptor itself.
Ventral globus pallidus-injured rats by kainic acid(10 mg) were used to derter-mine the monoamine levels in four different brain regions.In this model,a great decrease of NE con-centration was observed in both hippocampus and frontal cortex compared with nonnal contro.This result hints that a damage of noradrenergic neurons in this model has occurred. DA concentrations in the four brain zones after kainic acid injection were all reduced, but only in the frontal cortex and striatum the pronounced reductions were discovered while DA turnover rates in frontal cortex, stria-tum and meddullapons were significantly reduced. These results revealed a DA metabolic disorder occurring in these regions.However,5-HT concentrations as well as DBH activity, expressed by ratio of NE/DA,showed no marked difference in this model. In our study it is found that the changes of monoamine levels in this model basically reflect those discovered in AD patients.
