Sarcolipin (sln) and Sarcoplasmic Reticulum calcium ATPase pump (serca1) expression increase in Japanese medaka (Oryzias latipes) skeletal muscle tissue following cold challenge

Abstract

Endothermy is the process by which organisms maintain a constant body temperature despite dynamic environmental temperatures. There are two mechanisms organisms use to elevate body temperature: shivering thermogenesis (ST) and non-shivering thermogenesis (NST). Skeletal muscle NST is achieved through a futile Ca2+ cycling of sarcoplasmic reticulum Ca2+ ATPase (Serca1) in the presence of sarcolipin (Sln). Here we subjected Japanese medaka to a cold challenge to examine the expression of sln and serca1 transcripts from slow-twitch red and fast-twitch white muscle as environmental temperature decreased. We show a significant increase in relative sln and serca1 transcript expression in skeletal muscle tissues of cold-challenged Japanese medaka. The elevated transcripts support the role of Sln as a component of NST and support previous literature with the increase in serca1. To date, this is the first cold challenge on an ectothermic fish investigating sln transcripts. The ability of medaka to respond to a cold challenge with an increase in key calcium cycling components, specifically the calcium pump and sarcolipin suggest that teleost fish share a conserved transcriptional program in response to cold stimuli with fish species that possess the requisite anatomical adaptations to conserve metabolic heat.