Objective To investigate the effects of docosahexenoic acid (DHA) on large conductance Ca2+-activated K+ (BK) channels in normal retinal artery smooth muscle cells (RASMCs). Methods Cultured human RASMCs (6 th-8 th generations) were used to patch clamp experiment. The open probabihties (NP0) in BK channels with different concentrations (0.0, 1.0, 3.0, 5.0, 7.5, 10.0 μmol/L) of DHA were recorded by patch clamp technique in single channel configuration. RASMCs were intervened by different concentrations (0.0, 1.0, 5.0 μmol/L) of DHA as control group, low and high doses of DHA groups, respectively. The protein expressions of β subunit of BK channels in RASMCs from three groups were measured by Western blot. Results The NP0 of BK channels were 0.044 4±0.001 2, 0.081 2±0.004 2, 0.209 0±0.006 1, 0.310 5±0.005 3, 0.465 0±0.007 8 and 0.497 7±0.014 5 with perfusate of 0.0, 1.0, 3.0, 5.0, 7.5, 10.0 μmol/L DHA. DHA activated BK channels in a dose-dependent manner (F=2.621,P＜0.05). There was no significant difference in the protein expression of control group, low and high doses of DHA groups (F=11.657,P＞0.05). Conclusion DHA can directly activate BK channels, no increasing in subunit expression of BK channels.
PURPOSE:To investigate the relationship between the development of the diabetic retinopathy(DR)and the changes of ocular hemodynamics. METHODS:The hemodynamic parameters (Vmax,Vmin,RI)of central relinal artery(CRA )and central retinal vein(CRV)were measured both in the diabetes mellitus(DM) group(72 cases)and the control group(28 cases)with color Doppler flow imaging(Acuson-128XP/10). RESULT:The hemodynamic changes in CRA and CRV in the different stages of DR had their own characteristicS. The blood flow in CRA of the DM patients without DR was higher than that of the control (Plt;0.05). With tile deterioration of the retinopathy the blood flow in CRA decreased. The velocity of the blood flow in CRA of the proliferative DR group was less than that in the control ,DM without DR patients and background DR patients(Plt;0.05). The velocity of the flow in CRV of the DM patients was higher than that of control (Plt;0.001 )and exhibited its remarkable pulsative pattern. CONCLUSIONS:The changes of the hemodynamics in CRA.CRV was associated with the development of the diabetic retinopathy. （Chin J Ocul Fundus Dis,1997,13: 210-212 ）