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CHANGES IN CHARACTERISTICS OF SARCOPRASMIC RETICULUM AFTER INJECTION OF BUPIVACAINE INTO RAT TIBIALIS ANTERIOR

Yasuda, T1

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Medicine & Science in Sports & Exercise: May 2002 - Volume 34 - Issue 5 - p S183
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PURPOSE:

The alteration of characteristics in the sarcoplasmic reticulum (SR) of the rat tibialis anterior muscle (TA) was examined after injection of bupivacaine (BPVC) induced muscle damage.

METHODS:

Male Wistar rats (7wk) were randomly divided into two groups: control (n = 9) and BPVC infection (n = 9) groups. BPVC (0.5 ml of 0.5%) was injected into the right TA for BPVC group, then the TA dissected 24 h after injection. Histochemical and biochemical analyses were performed on the TA muscles. Transverse cryostat sections were stained with haematoxylin and eosin. SR Ca2+-ATPase activity in the presence and absence of the Ca2+ ionophore A23187 was measured according to the methods described by Simonides and van Hardeveld (1990).

RESULTS:

Twenty-four hours after BPVC injection, there was notable damage observed in the muscle, and the interstitium was infiltrated with mononuclear cells. BPVC injection evoked a 62% decrease in SR Ca2+-ATPase activity, and decreases in the ratio of the presence to absence of ionophore were observed in the BPVC muscle.

CONCLUSION:

These results suggest that BPVC injection caused the dysfunction of the Ca2+-ATPase protein and loss of SR vesicle membrane integrity. These alteration in SR function may contribute to the elevation of intracellular [Ca2+], which accounts for muscle fiber injury occuring after BPVC infection. Supported by Grant-in-Aid for JSPS Research Fellows 13780006

©2002The American College of Sports Medicine