Verapamil augments the neuroprotectant action of berberine in rat model of transient global cerebral ischemia

Abstract

Various potential molecules with putative positive role in stroke pathology have failed to confer neuro-protection in animal models due to their insufficient bioavailability in brain. Efflux of these molecules by P-glycoprotein (P-gp), on blood brain barrier (BBB) is one of the reasons of their poor bioavailability. Berberine, have anti-inflammatory, antioxidant, anti-apoptotic properties, but also having low oral bioavailabilty. Verapamil, which increased the central nervous system uptake of few drugs, when concomitantly administered with berberine was evaluated in this animal model. Wistar rats were subjected to bilateral common carotid artery occlusion to induce acute cerebral ischemia for 15min followed by reperfusion resulting in transient global cerebral ischemia. For 19 days berberine (5, 10, 20mg/kg, p.o.) alone and in similar doses concomitantly with verapamil (2mg/kg, p.o.) was evaluated employing various neuro-behavioral test, biochemical parameters and molecular estimations. The adjunction of berberine with verapamil improved the neurological outcome in a battery of behavioral paradigms, improved spatial memory in Morris water maze task, ameliorated the oxidative-nitrosative stress, increased acetylcholinesterase (AChE) activity, as well as improved mitochondrial complex (I, II, and IV) activity, reducing tumor necrosis factor-alpha, interleukin-1 beta and caspase-3 levels in brain tissues as compared to berberine alone group in ischemic rats. There is a strong possibility of improved brain bioavailabity of berberine when combined with verapamil. The findings suggested that the combination of berberine with verapamil, which could enhance its brain uptake, will surely provide a greater impact in neroprotection drug discovery for search of such combination.