Comparative Analysis of Force Reactions of Rat Hindlimb Muscles after Unilateral Compression of the Sciatic Nerve and Systemic Injections of Gamma-Hydroxybutyrate

Abstract

We compared force activity of the hindlimb muscles (ankle flexors and extensors and toe flexors) in rats subjected to course systemic injections of sodium gamma-hydroxybutyrate, GHOB (100 mg/kg, i.p., daily, during 4 weeks) after unilateral compression of the sciatic nerve (SN). Late effects of GHOB injections (10th and 12th weeks after surgery) were also analyzed. The contractile force of muscles was estimated using a tensometric technique. In the control group, animals were subjected to compression of the SN but were not injected with GHOB. In the experimental group, an appreciable functional loss (20-24%) was observed in muscles on the side of SN compression a week after surgery, while on the contralateral side we found a functional increment (60-17%). Within the 2nd to the 4th week of GHOB injections, stable force increments in both extensors and flexors (respectively, 2 and 2.5 times and by 20-50%) were manifested, while increments of the contractile force of muscles of the contralateral intact hindlimb (30-40%) did not depend on the function of the muscles. Within late time intervals (10th and 12th weeks) after surgery, the contractile force of muscles of the injured and contralateral hindlimbs increased maximally by 30-40%, as compared with to the control; this increment in the injured hindlimb was observed in extensors, while it was manifested in flexors of the contralateral hindlimb.