COUPLING OF SPINAL LOCOMOTOR NETWORKS IN LARVAL LAMPREY REVEALED BY RECEPTOR BLOCKERS FOR INHIBITORY AMINO-ACIDS - NEUROPHYSIOLOGY AND COMPUTER MODELING

作     者：HAGEVIK, A MCCLELLAN, AD 

作者机构：UNIV MISSOURIDIV BIOL SCICOLUMBIAMO 65211 

出 版 物：《JOURNAL OF NEUROPHYSIOLOGY》 (神经生理学杂志)

年 卷 期：1994年第72卷第4期

页      面：1810-1829

核心收录：

中图分类：Q4[生物科学-生理学] 

学科分类：0710[理学-生物学] 07[理学] 071003[理学-生理学] 

基　　金：NINDS NIH HHS [NS-29043] Funding Source: Medline 

摘      要：1. Receptor blockers for inhibitory amino acids were applied to part or all of the spinal cord of larval lamprey during brain stem-initiated locomotor activity. Blocking glycinergic inhibition with strychnine applied to the entire spinal cord converted the locomotor pattern from left-right alternation to synchronous left-right bursting. The results suggest that left and right oscillators are connected by relatively strong reciprocal inhibitory( glycinergic) connections in parallel with weaker reciprocal excitatory connections. This possible organization was supported by results from a computer model consisting of left and right oscillators connected by reciprocal inhibition and excitation in parallel. In addition, the results suggest that reciprocal inhibition is not required for left-right rhythmicity but rather is involved primarily with phasing of left-right activity. 2. Locally blocking glycinergic inhibition with strychnine in the rostral spinal cord resulted in synchronous left-right burst activity in that region of the cord as well as in more caudal areas of the cord in which reciprocal inhibition should still be functional. 3. Blocking glycinergic inhibition in the caudal spinal cord converted the pattern in that region of the cord to left-right synchronous activity. The effects in the ascending direction on the burst patterns in more rostral areas of the spinal cord were less than those mentioned above in the descending direction with application of strychnine to the rostral spinal cord. 4. With glycinergic inhibition or GABAergic inhibition blocked in the entire spinal cord, stable longitudinal coupling along the spinal cord persisted. This and the neurophysiology results mentioned above suggest that the main mechanism for longitudinal coupling between locomotor networks in adjacent regions of the spinal cord is ipsilateral excitatory connections and not crossed inhibitory connections. This possible organization was supported by results from a computer mod