GPR56 mRNA Expression Is Modulated by Acute and Chronic Training Variable Manipulations in Resistance-Trained Men

Abstract

Background: Skeletal muscle adaptations are affected by resistance training (RT)-induced acute and chronic transcriptional responses. An under-explored gene target involved in mechanotransduction is the expression of the G protein-coupled receptor 56 (GPR56). However, studies investigating the acute and chronic effects of RT manipulations on GPR56 mRNA are scarce. Methods: Twenty subjects had each leg randomly assigned to a standard ((CON) no specific manipulation) or a variable RT (manipulations in load, volume, muscle action, and pause in a session-by-session fashion (VAR)). GPR56 mRNA expression was assessed before and after 16 training sessions (chronic effect) and 24 h after a 17th session (acute effect). Results: Acute GPR56 mRNA expression increased at 24 h (p < 0.01) without differences between CON and VAR (p > 0.05). No differences were found in GPR56 mRNA expression when comparing each VAR condition (load vs. sets vs. eccentric actions vs. pause) nor with CON at 24 h (p > 0.05). Chronic GPR56 mRNA expression increased at Post compared with Pre (p < 0.02) for VAR only, with a tendency (p = 0.058) toward higher expression for VAR as compared with CON. Conclusion: GPR56 mRNA expression is acutely and chronically modulated by RT. Additionally, chronic GPR56 mRNA expression is modulated by RT variable manipulations.