Role of O2 and K+ in abolition of sympathetic vasoconstriction in dog skeletal muscle

Abstract

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

Attenuated Vasodilator Responses to K+ in Essential Hypertensive Men

“…Therefore we repeated analysis of covariance omitting responses in the five youngest normotensive subjects so there was no longer a significant difference in ages. Results of this analysis were similar to the results using data from the entire group; responses IR (mm Hg/mI /min/100 cm3 o io 20 intervals (Fig. 1c) (14).…”

“…limb, rather than a response to systemic effects of the ion (3,19). It is likely that the response we observed is, at least in part, independent of local neural structures (20), because in the dog the response is not blocked by phentolamine or nerve section (3). Furthermore, the response is observed in vitro and is not blocked by tetrodotoxin (18).…”

“…At time of study the normotensive subjects were convalescing, afebrile, and not receiving vasoactive drugs, including digitalis preparations. 20 patients had essential hypertension of mild to moderate severity documented by thorough study which included hospital diastolic blood pressures averaging above 90 mm Hg during hospital days 4-6, normal rapid sequence intravenous pyelograms, normal 24 h urine vanilmandelic acid excretion, and normal serum sodium, potassium, and calcium concentrations. Renal angiography was performed on one patient (C. L. V.) and interpreted as indicating no abnormalities.…”

Neural control of muscle blood flow during exercise

“…In contrast, a study in humans has implicated local tissue hypoxia as an important factor in the attenuated vasoconstrictor response to SNA in exercising muscle (34). This effect of hypoxia may be enhanced by physiologically relevant increases in [K ϩ ] o (81), indicating the potential for additive or synergistic effects of metabolic signals on vascular regulation in exercising muscle. Another factor that is reported to mediate functional sympatholysis in rodents (88 -90) and in some (13,73), but not all (20), human studies is NO.…”

On the mechanism of rhabdomyolysis in potassium depletion

“…Although the mechanism by which potassium deficiency leads to rhabdomyolysis has not been elucidated, impressive evidence (8)(9)(10)(11) has accumulated that potassium release from contracting skeletal muscle cells into interstitial fluid of the muscle directly dilates adjoining arterioles, and thereby, the potassium ion may be a major factor mediating the rise of muscle blood flow which normally occurs with exercise. Accordingly, it might be postulated that if potassium release from potassium-deficient skeletal muscle is impaired during intense exercise, muscle injury or frank necrosis could ocur as a consequence of relative ischemia.…”