[Effects of L-glutamate microinjection into the ventral horn of spinal cord gray matter on gastrocnemius contractility in toad].
A diagram of motor neuron pool of ventral horn of spinal cord gray matter in toad was first delineated. Different concentrations (1, 0.5, 0.1, 0.01 mol/L) of excitatory amino acid L-Glu or physiological saline (0.65% NaCl) were then microinjected into the motor neuron pool in a urethane-anaesthetized toad. The contraction curve of the gastrocnemius was then recorded by the BL-420 Physiological Signal Recording. We took the maximal tension, the duration of rising phase, the velocity of tension variation, and the duration of descending phase as the parameters to study the characteristic of gastrocnemius contractility. It was found that the gastrocnemius contractility of all the 4 groups was tetanus but differed in degree, especially the maximal tension, and velocity of tension variation. In contrast to physiological saline, gastrocnemius contracted by the stimulation of L-Glu, and the contraction parameter showed dose-effect relationships except for the duration of descending phase, which was caused by the combination rate of L-Glu and the receptor.
Lu
Chang-Liang
CL
Key Laboratory of Animal Resistance of Shandong Province, College of Life Sciences, Shandong Normal University, Jinan 250014, China.
Zhang
Xiao-Meng
XM
Zhu
Jian-Ping
JP
Ai
Hong-Bin
HB
D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects* / Q000502:physiology; D002025:Bufonidae / Q000502:physiology*; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage*; D008297:Male; D008845:Microinjections; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology
D018698:Glutamic Acid