Identification of the main generator source of longitudinal muscle contraction in the earthworm ventral nerve cord
Braz. j. med. biol. res
;
31(10): 1285-94, Oct. 1998. ilus
Artigo
em Inglês
| LILACS
| ID: lil-223990
RESUMO
The main generator source of a longitudinal muscle contraction was identified as an M (mechanical-stimulus-sensitive) circuit composed of a presynaptic M-1 neuron and a postsynaptic M-2 neuron in the ventral nerve cord of the earthworm, Amynthas hawayanus, by simultaneous intracellular response recording and Lucifer Yellow-CH injection with two microelectrodes. Five-peaked responses were evoked in both neurons by a mechanical, but not by an electrical, stimulus to the mechanoreceptor in the shaft of a seta at the opposite side of an epidermis-muscle-nerve-cord preparation. This response was correlated to 84 per cent of the amplitude, 73 per cent of the rising rate and 81 per cent of the duration of a longitudinal muscle contraction recorded by a mechano-electrical transducer after eliminating the other possible generator sources by partitioning the epidermis-muscle piece of this preparation. The pre- and postsynaptic relationship between these two neurons was determined by alternately stimulating and recording with two microelectrodes. Images of the Lucifer Yellow-CH-filled M-1 and M-2 neurons showed that both of them are composed of bundles of longitudinal processes situated on the side of the nerve cord opposite to stimulation. The M-1 neuron has an afferent process (A1) in the first nerve at the stimulated side of this preparation and the M-2 neuron has two efferent processes (E1 and E3) in the first and third nerves at the recording side where their effector muscle cell was identified by a third microelectrode.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Oligoquetos
/
Contração Muscular
/
Neurônios
Tipo de estudo:
Estudo diagnóstico
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
1998
Tipo de documento:
Artigo
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