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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 367 (1976), S. 37-42 
    ISSN: 1432-2013
    Keywords: Acetylcholine ; Atropine ; Inderal ; Sympathetic system ; Phosphorylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 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. The AMP content did not increase with the initiation of the vasomotor effect, and this fact suggests that the increase in phosphorylase activity is due to an increase in phosphorylase “a” rather than to the activation of phosphorylase “b” by AMP. Atropine blocks both the dilator effect and phosphorylase activation elicited by sympathetic stimulation. Acetylcholine, injected intraarterially or added to a muscle homogenate, increases phosphorylase activity. It is concluded that acetylcholine, released by sympathetic nerve endings, performs a second mediator function, that of activating anaerobic metabolism in the skeletal muscle. The two mediator functions of acetylcholine seem to be spatially delimited.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2013
    Keywords: Cholinergic vasodilatation ; Skeletal muscle performance ; Acetylcholine ; Atropine ; Adrenaline ; Propanolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 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. slows down the rate of decrease of contraction. The effect is abolished by atropine (0.5 mg/kg) and insensitive to propanolol (0.1 mg/kg). The cholinergic influence is only effective if hypothalamic stimulation coincides with the beginning of motor nerve stimulation. In some of our experiments stimulation of the same central structures elicited another influence on muscle performance, associated with the release of adrenaline into the blood. In this case, contrary to the cholinergic influence, the force of contraction increases only when hypothalamic stimulation does not start earlier than 100 s after the initiation of contraction (phase of slow decline of tension). The effect is insensitive to atropine (0.1 mg/kg) and abolished by propanolol (0.1 mg/kg).
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2013
    Keywords: Mental arithmetic ; Skeletal muscle blood flow ; Evoked contraction of skeletal muscle ; Muscle metabolism ; McArdle's syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanism of the increase of muscle performance and of vasodilation during emotional stress was studied. The “emotional” increment of voluntary performance does not depend on the level of blood supply to the working muscles, and the effect is maintained under conditions of cessation of arterial inflow. Augmentation of muscle performance is also observed during emotional stress when isometric contraction is evoked by electrical tetanic stimulation of the nerve, when the number of muscle fibres participating in the evoked response does not increase during emotional stress. The “emotional” vasodilation is greatly reduced in patients suffering from McArdle's syndrome, in whom the normal course of glycolysis in muscles is disrupted. It is suggested that acetylcholine liberated from sympathetic fibres causes the activation of glycolysis in muscles, which in its turn induces vasodilation in resting skeletal muscles and increase of muscle performance during emotional stress.
    Type of Medium: Electronic Resource
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