Ionic Mechanisme Action Of Severals Amino Acids on Leech Ganglia


Abdul Manan Mat Jais


The Fifteenth Malaysian Biochemical Society In Conference : Focus on Biochemistry in Malaysia in the 1990's, Faculty Of Medicine Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia.




leech, Hirudo medicinalis, ionic mechanisms, amino acids


Intracellular recordings were made from Retzius cells of the leech, Hirudo medicinalis, and ionic mechanisms of L-glutamate, ibotenate, quisqualate and kainate were examined. In Na+ free Ringer, all the amino acids responses were abolished or greatly reduced. However, the increase in Ca** (10 mM) resulted in the recovery of the kainate, and some of the quisqualate reaction. Cobalt had blocked the kainate response in Na* free high Ca+* Ringer. All the amino acids responses were associated with an increase in conductance: L-glutamate and ibotenate are dependent on sodium; quisqualate is mainly sodium dependent with a small calcium component; but the calcium can completely substitute for the sodium vrNa+free high Ca** Ringer. These studies provide evidence that L-glutamate and ibotenate act on a common receptor, while quisqualate and kainate on different receptors.