The aim of our study was the investigation of the morphological changes of cardiovascular system, caused by NO inhibition during the laser irradiation of low-frequency. On reception of L NAME and a low-frequency laser irradiation arterial pressure during all experiment remains within the norm. At slight increase of phonic arterial pressure the laser irradiation proved to be less effective, while on a background of high arterial pressure the irradiation does not interfere the further development of hypertension and persistency. Immediately after reception of L NAME and at a low-frequency laser irradiation, the fibrosis and inflammatory changes of myocardium have not been observed; on the background of the slight enhancement of arterial pressure, laser irradiation causes insignificantly expressed fibrosis, inflammatory changes in myocardium; while on the background of increased arterial pressure a laser irradiation doesn't interfere development of fibrosis, myocardium and inflammatory changes in it. Immediately after reception L NAME and at a laser irradiation of low-frequency from the third day, a damage of cardiovascular walls, inflammatory changes, perivascular fibrosis have not been developed, while on the background of increased arterial pressure the irritation doesn't interfere the development of the above mentioned changes. Thus, the irradiation of a low-frequency laser might be recommended to prevent the development of hypertension and to avoid the complications of pre-clinical phase of hypertension. Though, the analogous recommendations are not foreseen for involvement in algorithm of the treatment of hypertension and correction of clinical evidence of the disease.