Species Distribution of Sympathetic Cholinergic Vasodilator Nerves in Skeletal Muscle

Abstract

The lumbar sympathetic chain was electrically stimulated in different species before and after blocking the adrenergic vasoconstrictor nervous response. Blood flow in the hind limb skeletal muscles was measured. In all species studied, fox, sheep, goat, monkey (five different strains), polecat, rat, badger, opossum rat and hare, stimulation of the lumbar chain before adrenergic blockade resulted in a vasoconstriction. After blocking the vasoconstrictor nervous response stimulation elicited a blood flow increase in fox, sheep and goat. After atropine, the response to stimulation was blocked, indicating that sympathetic cholinergic nerves had been activated. In the other species studied no vasodilator response was observed upon sympathetic chain stimulation. The results suggest that the role attributed to the vasodilator nerves, anticipatory to muscle exercise, are played by other mechanisms in species lacking sympathetic cholinergic vasodilator nerves.

The pontomedullary area integrating the defence reaction in the cat and its influence on muscle blood flow

“…The conclusion that inhibition of the normal vasoconstrictor tone in skeletal muscle is part of the pattern of cardiovascular response elicited from the brain stem areas integrating the defence reaction is relevant to the recent observations of Bolme, Novotny, Uvnas & Wright (1970) that, while there are cholinergic vasodilator nerve fibres supplying the skeletal muscles of the sheep, goat and fox (in addition to the cat and dog), there are none to those of the rat, badger, polecat, hare or a variety of monkeys. Likewise, though there is no doubt that muscle vasodilatation is an important component of the defence reaction in man, it is not always possible to reduce the dilatation by administering atropine, in which case it seems due to circulating catecholamines (Barcroft, Brod, Hejl, Hirsjairvi & Kitchin, 1960).…”

The influence of the sympathetic nervous system on individual vessels of the microcirculation of skeletal muscle of the rat

“…Whilst this dilator influence might be overcome under most circumstances by the direct action of sympathetic vasoconstrictor activity it seems possible that under circumstances such as the alerting stage of the defence reaction when vasoconstrictor activity to skeletal muscle may be reduced (Coote, Hilton & Zbrozyna, 1973), the simultaneous release of adrenaline from the adrenal medulla (Grant, Lindgren, Rosen & Uvnas, 1958) may significantly augment the increase in muscle blood flow. Such a hormonally mediated dilatation might be of particular importance in an animal such as the rat which is reputed to have no sympathetic cholinergic dilator supply to skeletal muscle vasculature (Bolme, Novotny, Uvnas & Wright, 1970).…”

An analysis of the purinergic component of active muscle vasodilatation obtained by electrical stimulation of the hypothalamus in rabbits

“…Builbring & Burn (1937) discounted the existence of a vasodilator system in the skeletal muscle of both monkeys and rabbits, and no evidence for sympathetic vasodilator fibres in rabbits could be uncovered by Rosenblueth & Cannon (1935). Uvnas and co-workers examined numerous species for the presence of active muscle vasodilatation (Uvnas, 1966;Bolme et al, 1970) but most, including 5 types of monkey, the hare, and the rabbit, were reported to be without skeletal muscle vasodilator fibres. Contrary to these early studies, Schramm et al (1971) provided evidence for sympathetic muscle vasodilatation in the monkey.…”