Seasonal effects on water and osmotically-active ionic contents (Na+, K+ & Cl�??) of skeletal muscles of the spiny-tailed lizard, Uromastix hardwickii

Abstract

Muhammad Saleh Soomro, Muhammad Abdul Azeem, Muhammad Naeem Soomro, Rehana Rehman Rehman

To assess the seasonal effects on water & osmotically-active ionic contents (Na+, K+ & Cl-) of skeletal muscles of the spiny-tailed lizard Uromastix hardwickii. Fresh animals (adults) of both the sexes were used in all the experiments, and the gastrocnemius (skeletal) muscles were dissected out, reptilian buffer solution was used to keep dissected muscles moist & used during experimentation. The muscle sample solutions were prepared by heating/drying and incinerating/ashing the muscle tissues, treating with acid and deionized water respectively. These samples were then used for the estimation of Na+, K+ & Cl- ions. The water content was found as percent wet muscle weight. The average mean values of water content and these osmotically active ionic contents were found to fall significantly (P<0.05) from peak winter towards peak summer & vice versa. The seasonal effects of these parameters, studied for the first time in the skeletal muscle of Uromastix hardwickii, displayed changes as the animal passed from one seasonal phase to another. Hence seasonal changes are invariably associated with changes in environmental temperature, and definitely responsible to change the active behavior and homeostasis of these animals from summer towards winter by variations in blood borne humoral and hormonal substances along with significant changes in osmolality and tissue water contents.