The effect of hemiplegia on plasma endothelin levels in the elderly

Endothelin is a potent endothelium-derived vasoconstrictor peptide. Its plasma levels fluctuate in relation to a variety of physiological and pathophysiological conditions. It has been reported that in hemiplegic patients blood pressure may be increased or decreased in the plegic ann according to the tone, spastic or flaccid, respectively, of the ann. To elucidate the pathophysiological significance of endothelin in hemiplegia blood pressure alterations, we measured the plasma endothelin levels of twelve elderly patients, both in the plegic and unaffected arm. Seven of them were affeted by spastic and five of them by flaccid hemiplegia, based on haemorrhagic or ischemic stroke. Plasma endothelin concentrations were significantly higher (p<0.05) in the plegic arms (4.84 ± 1.66 pg/ml) than in the unaffected ones (4.48 ± 1.67 pg/ml) of patients independent of the spastic or flaccid tone. The increased level of plasma endothelin in the plegic arm suggests that endothelin does not take part in the hemiplegia blood pressure alterations. Endothelin could nevertheless be involved in the regulation of the vessel wall tension and may operate in blood volume homeostasis by mantaining the strict relationship between the venous wall and the intravascular volume.