[Effect of monoiodoacetate and ouabain on cholinergic vasodilation in cat skeletal muscles].

The effects of a glycolysis blocking agent monoiodoacetate and of the sodium pump blocker ouabain, on cholinergic vasodilatation in skeletal muscle were studied. In acute experiments on cats, i. v.

Increase in osmolality of venous blood from skeletal muscle during cholinergic vasodilatation.

The arterio-venous difference in the osmolality of blood plasma of cat m. triceps surae was studied during sympathetic cholinergic nerve excitation. The vasodilatation was induced by stimulation of hypothalamus or the sympathetic chain, the latter after alpha-adrenoceptor blockade.

[Changes in plasma composition resulting in an increase in the osmotic pressure of venous blood during the cholinergic dilatation effect].

Stimulation of the sympathetic chain in the presence of alpha-receptor blocking agents caused cholinergic vasodilatation of the cat hind-limb vessels. The arterial-venous difference with respect to osmotic pressure (Posm), as well as to the content of K+, Na+, Ca2+, lactate, total protein, and inorganic phosphate was determined in blood samples collected during vasodilatation. Sympathetic stimulation in the presence of alpha-receptor-blocking agents agents increased the conductance of the hind-limb vessels and Posm of the venous blood (7.

[Cholinergic sympathetic influences on blood flow and cyclic nucleotide concentration in skeletal muscles].

The content of 3.5 cGMP increased twofold and the content of 3.5 cAMP remained unchanged in the cat skeletal muscle during vasodilatation evoked by hypothlalamic stimulation.

The content of cyclic nucleotides (3',5'-cGMP and 3',5'-cAMP) in cat skeletal muscle during sympathetic cholinergic vasodilatation.

Phosphorylase activity and content of cyclic GMP and AMP were investigated in the gastrocnemius muscle of the cat during the development of cholinergic vasodilatation evoked by stimulation of the hypothalamus. Samples of muscle tissue were taken during an early stage of the vascular effect. One of the hindlimbs was denervated and served as control.

Cholinergic and adrenergic influences upon cat skeletal muscle performance induced by stimulation of the anterior hypothalamus.

The influence exerted by stimulation of the anterior hypothalamus (zone of cholinergic vasodilatation) on the performance of triceps surae during tetanic contraction has been investigated. Hypothalamic stimulation, if combined with indirect muscle stimulation, improves muscle performance, i.e.

Activation of anaerobic metabolism in cat skeletal muscle during cholinergic sympathetic vasodilatation.

Phosphorylase activity was found to increase 2-fold as compared with the control value (79% and 39% respectively) within the first 2-3 s of the vasomotor effect elicited in the skeletal muscle by sympathetic stimulation. Phosphorylase activity was still high during the period of maximum blood flow, although to a lesser extent (54% and 45%). During the phase of restoration of the initial rate of blood flow the values of phosphorylase activity were the same in the experimental and the control sample.

[Effect of acetylcholine on phosphorylase from skeletal muscle].

Acetylcholine (1-10(-5) g/ml) was shown to increase the content of active form of phosphorylase A in homogenate of cat skeletal muscle. Atropine (1-10(-5) g/ml) diminished acetylcholine-induced increase in the phosphorylase activity from 22% to 5.28%.