Effects of a calcium channel blocker on electrical activity in myofascial trigger spots of rabbits.
OBJECTIVE
This study investigated the effect of a calcium channel blocking agent, verapamil, on the spontaneous electrical activity (SEA) in a myofascial trigger spot of biceps femoris muscles of rabbits.


METHODS
Left and right legs of eight adult New Zealand rabbits were randomly assigned into either experimental or control groups to assess the effect of verapamil on SEA. Verapamil and normal saline were injected into the external iliac artery for experimental and control groups, respectively. The experiment was divided into two phases: Phase A investigated the immediate effect of verapamil on SEA of one active locus, and phase B studied the effect of verapamil on SEA of 25 different active loci. The average integrated value of SEA was used to statistically analyze the effect of verapamil on myofascial trigger-spot sensitivity.


RESULTS
In phase A, conducted on one active locus, the regression analysis results showed that the average integrated value in the verapamil group linearly decreased with time, but the average integrated value did not significantly change with time in the control group. In phase B, which analyzed 25 different active loci, the results indicated that the mean average integrated values in the verapamil group was significantly lower than that of the control group.


CONCLUSIONS
Calcium channel blockers can effectively inhibit the SEA of myofascial trigger spots.
Hou
Chuen-Ru
CR
Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China.
Chung
Kao-Chi
KC
Chen
Jo-Tong
JT
Hong
Chang-Zern
CZ
D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004195:Disease Models, Animal; D004576:Electromyography; D006614:Hindlimb / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009209:Myofascial Pain Syndromes / Q000503:physiopathology*; D011817:Rabbits; D012044:Regression Analysis; D014700:Verapamil / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D014700:Verapamil