[Changes in transcapillary fluid exchange and the distensibility of small intestinal blood vessels upon adrenergic stimulation].
In acute experiments on cats, the mean coefficient of capillary filtration (CFC) in denervated small intestine was 0.10 ml/min/mm Hg/100 g and the stretching ability of the intestinal venous vessels was 0.21 ml/mm Hg/100 g. Infusion of noradrenaline (5 micrograms/min) reduced the CFC by 33% and the stretching ability by 24%. Blockade of vascular alpha-adrenoreceptors abolished and beta-adrenoreceptors augmented the noradrenaline effect on CFC and stretching ability. The data obtained indicate presence of both alpha- and beta-adrenoreceptors in precapillary sphincters and venous vessels of small intestine. Stimulation of the alpha-adrenoreceptors entails constriction of precapillary sphincters and decreases venous stretching ability whereas stimulation of beta-adrenoreceptors leads to opposite effects. Noradrenaline exerts main effect on alpha-adrenoreceptors of precapillary sphincters and venous vessels in the denervate intestine; alpha-blockade is followed by an obvious beta-effect in the form of relaxation of precapillary sphincters and increase of the venous stretching ability.
D000818:Animals; D001808:Blood Vessels / Q000032:analysis; D002199:Capillary Permeability; D002415:Cats; D003714:Denervation; D007421:Intestine, Small / Q000098:blood supply* / Q000294:innervation; D009638:Norepinephrine / Q000494:pharmacology*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D014664:Vasodilation; D014690:Venous Pressure / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D009638:Norepinephrine
Izmeneniia transkapilliarnogo obmena zhidkosti i rastiazhimosti venoznykh sosudov tonkogo kishechnika pri adrenergicheskoĭ stimuliatsii.