Effect of opioid lymphostimulation on the microcirculation in pial vessels of the ischemized rat brain

The response of pial vessels to i.p. administration of leu-enkephalin (at 40 μg/kg) is studied biomicroscopically in the control, before and after bilateral occlusion of the common carotid arteries. Leu-enkephalin causes chiefly the narrowing of pial arterioles and does not affect venule diameter. The effect of leu-enkephalin on occlusion of the common carotid arteries manifests itself in the preservation of circulation stability, the narrowing of some arterioles, and in the decrease of the degree of dilation. These changes occur against the background of lowered arterial pressure, bradycardia, increased local circulation in the brain cortex by 50–70%, intensification of the lymph flow in micro- and macrovessels, and the absence of mortality of animals in the first hours of occlusion of the arteries. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 100–105, January, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences