| Danshen and gegen are used in traditional Chinese medicine for the treatment of cardiovascular diseases. In this study, the relaxant actions of a danshen and gegen formulation (DG; ratio 7:3) and its constituents were investigated on rat-isolated cerebral basilar artery. In addition, the neuroprotective effect of DG was explored in rats subjected to global and focal ischaemia.;DG and all its constituents produced concentration-dependent relaxation of the artery rings precontracted by U46619. Removal of the endothelium had no effect on their vasodilator actions except the maximum response ( Imax) to puerarin was inhibited by 42%. The nitric oxide synthase (NOS) inhibitor L-NAME and guanylyl cyclase (GC) inhibitor ODQ but not the cyclo-oxygenase (COX) inhibitor flurbiprofen produced partial inhibition on the puerarin-induced effect. In a set of endothelium-denuded artery rings, adenylyl cyclase (AC) inhibitor SQ22536, GC inhibitor ODQ, KV channel inhibitor 4-aminopyridine (4-AP) and BKCa channel inhibitor iberiotoxin had no influence on their vasodilator actions. However, pretreatment with KATP channel inhibitor glibenclamide reduced Imax to DG, danshen, gegen, danshensu, puerarin, daidzein and daidzin. KIR inhibitor barium chloride (BaCl2) reduced Imax to salvianolic acid B and daidzein. The non-selective K+ channel inhibitor tetraethylammonium (TEA), or a combination of all the K+ channel inhibitors produced significant partial inhibitions on all the agents’ actions. Electrophysiological studies on smooth muscle cells isolated from rat basilar artery also confirmed that DG, danshen, gegen danshensu, puerarin, daidzein and daidzin elevated KATP currents. In addition, DG and all its constituents, except puerarin, produced concentration-dependent inhibition on CaCl2-induced vasoconstrictions. These findings were confirmed by con-focal microscopy studies.;In vivo study on a rat model of global ischaemia showed that challenging the rats with 10 min bilateral common carotid artery occlusion combined with hypotension, and followed by 24 h reperfusion produced significant decrease in cerebral blood flow and oxidative damage compared to sham-operated animals. Administration of DG (0.3 g/kg and 3 g/kg, p.o.), danshen (3 g/kg, p.o.) or gegen (3 g/kg, p.o.) for 7 days had no effect on blood pressure. However, the 7 days treatment with DG (3 g/kg) restored superoxide dismutase (SOD) and catalase (CAT) activities, suppressed the production of maleic dialdehyde (MDA), and inhibited the production of nitric oxide (NO). In addition, gegen (3 g/kg) restored SOD enzyme activity, whereas, danshen (3 g/kg) inhibited NO production. In addition, treatment with DG (3 g/kg) showed a significant reduction in infarct weight and improved the neurological deficit in a rat model of focal cerebral ischaemia induced by middle cerebral artery occlusion (MCAO). |
