Vasorelaxation to Eugenol, Curcumin and Nanocurcumin mediated by differential augmentation of Na+, K+-ATPase activity in middle uterine artery of Capra hircus

Abstract

Sodium-potassium ATPase (<em>Na, K</em>-<em>ATPase)</em> is an integral protein universally distributed in the plasma membrane of all eukaryotic cells. It regulates trans-epithelial sodium ion transport, muscle contraction, nerve excitability, secretary functions and intracellular signaling. We investigated the mechanism of vasorelaxation effect of Eugenol, Curcumin and Nanocurcumin in the middle uterine artery (MUA) of goat to evaluate their possible therapeutic potential in hypertension during pregnancy or pre-eclampsia. The UA rings were isometrically contracted by K⁺-free MKHS to plateau and relaxed with KCl (10 &mu;M-10 mM) following standard protocol. The K⁺-vasorelaxation response (VR) was taken either in presence of ouabain with or without Eugenol/Curcumin/Nanocurcumin (10 &mu;M). R_max (maximum % vasorelaxation) of K⁺-induced VR-curve elicited in UA rings was reduced (from 6.90% and 26.55%) to 4-5% in presence of Ouabain in both NP and P goats. R_maxobtained from KVR curve elicited in UA rings were augmented in presence of Eugenol (NP: 16.22%, P: 42.67%) or Curcumin (NP:21.23%, P:35.49%) or Nanocurcumin (NP:6.91%, P:34.88%). K⁺vasorelaxation was inhibited in presence of Ouabain and Eugenol/ Curcumin/Nanocurcumin (R_max: 6.11%, 9.18%, 4.11% in non-P, respectively) and (R<em>_max:</em> 5.40%, 3.39%, 6.00% in P, respectively). The results indicated that (i) there is increased function of &alpha;₁- Na⁺, K⁺-ATPase in UA of P goats (ii) Eugenol, Curcumin and Nano-curcumin differentially augmented the function and expression of &alpha;₁isoenzymes of sodium pump in UA of non-P and P goats. Thus, the polyphenols potentially activate &alpha;₁ isoenzymes of Na⁺-K⁺-ATPase and could possibly be useful as therapeutic in hypertension during pregnancy.