| 3, 4-dihydro-2-(4-morpholinylmethy)-1(2H)-naphthalenone (CY) was first synthesizedby Welch, Willard M et al. in 1977 and its low analgesic activity was reported. There is nofurther study about CY. The purpose of this study was to investigate for the first time therelaxing effect of CY on vascular smooth muscle (VSM). To investigate the effect andmechanism of CY on VSM, experiments were carried out on isolated VSM from rabbits,guinea pigs and rats. The effects and mechanism of CY on VSM preparations contractedwith stimulants were studied on. In addition, the effect of CY was also investigated on theECG, respiration, blood pressure of anesthetized rats. The results suggested that CY(3×10-6～3×10-3 mol/L) has a potent relaxing effect on VSM preparations contracted withadrenaline(AD), noradrenaline(NE), High-K+ solution or BaCl2．Furthermore, therelaxation of CY can not be blocked by indometacin, methylene blue, glibenclamide andverapamil. However, the mechanism of CY had relationship to methylene blue,glibenclamide and veripamil. The maximum responses of the cumulativeconcentration-response curves to NE, KCl or CaCl2 were depressed by CY(10-5 , 10-4 and10-3 mol/L). The phasic contraction produced by NE in calcium-free medium with EDTAwas concentration dependently attenuated with CY (10-5 ,10-4 and 10-3 mol/L) pretreatment.In this paper, these results indicated that CY (5．34, 10．68mg/kg) and amlodipineinhibited obviously the systolic pressure (SBP), diastolic pressure (DBP), and mean arterialpressure(MAP) in anesthetized rats by i.p. administration, but CY and amlodipine can notinfluence the heart rate, T wave height, S-T segment height and respiratory frequency ofanesthetized rats. Overall, the effects of CY on vascular smooth muscle preparations in this study suggestthat CY has a potent relaxing effect on VSM preparations. The mechanism was associatedwith the blockade of Ca2+ channels. In addition, cGMP-related relaxation and the openingof KATP channel; moreover, the inhibition of intracellular release of Ca2+ may be alsoinvoked as one of the main mechanism involved in the vasorelaxant action of CY. |
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