Enhanced Efficacy of the Commissural Transmission between Lateral Giants in the Sensitization of Crayfish Escape Behavior

• 영문명: Enhanced Efficacy of the Commissural Transmission between Lateral Giants in the Sensitization of Crayfish Escape Behavior
• 발행기관: 대한생리학회
• 저자명: C.Lee, Sun-Hee
• 간행물 정보: 『대한생리학회지』제29권 제2호, 291~300쪽, 전체 10쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1995.12.31

영문 초록

Lateral giant (LG)-mediated escape response of crayfish is sensitized by natural traumatic events. Such sensitization has previously been shown to be associated with increased transmission between primary afferents and sensory interneurons at the cholinergic synapse of LG escape reflex circuit. In the present study, it was firstly investigated as to whether transmission is also altered at other synapses of the LG-escape reflex circuit by traumatic shock-induced sensitization. Evidence that traumatic shock also directly affects the excitability of lateral giants is now provided by the finding that traumatic shock produces a significant reduction of the time needed for LG to recruit its contralateral homologue, which is defined as commissural delay. Octopamine, a naturally occurring neuromodulator in the crayfish nerve cord, has also been shown to enhance transmission at the cholinergic synapse between primary afferents and sensory interneurons, and has been conjectured to mediate sensitization. Like traumatic shock, octopamine (10^-5-5 X 10^-4 M) also enhanced the efficacy of commissural transmission between lateral giants, as indicated by a significant reduction of commissural delay. This effect was blocked by an octopamine antagonist phentolamine, suggesting a specific action of octopamine on the octopamine receptor present on LGs. These observations suggest that both traumatic shocks and octopamine may cause a rather broad alteration in the excitability of the crayfish nervous system that contributes to the sensitization of the LG escape response.

키워드

Sensitization Octopamine Commissural transmission Crayfish escape behavior Lateral giants