Two kinds of peripheral afferent neurons in the earthworm reflex arc

Chang, Y.C.; Marchioro, Murilo; Assmé, Z

doi:10.1016/0300-9629(91)90370-r

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…Thus, only the last 13 pairs were physiologically identi- Figure 4R) (9) are two parallel bundles of longitudinal processes separated by a distance of no more than 100 µm and a group of varicosities (V; Figure 4R) on the right side and in the dorsal quadrant of the ventral nerve cord when viewed in the anteroposterior direction ( Figure 4AP). A thin process with a series of curves shorter than 30 µm, a unique characteristic of neuron process (8,9), can be seen coming in from the ipsilateral (left) first nerve (A1; Figure 4R) to the medial longitudinal bundle, and two thin processes can also be seen going out of the lateral longitudinal bundle through the contralateral (right) first (E1; Figure 4R) nerves. These are the afferent and efferent fibers with their responses recorded as N l and N r in Figure 2.…”

Section: Synaptic Connection Between the Main Generator Neuronsmentioning

confidence: 96%

“…Only the middle body between the 25th and 70th segments was used for their repeated neuronal organization (17) important for reproducible results. Dissection of the EMNC (Figure 1), electrophysiological equipment and experimental procedures were described in previous articles (8,9).…”

Section: Methodsmentioning

confidence: 99%

“…Our first objective was to identify the neural substrate of a main generator source of muscle contraction and another study (1) was conducted to identify the neural substrate of a modulator with a facilitatory effect on this main generator source. These two neural substrates may either be the known neurons identified by us (8,9) or by others (10,11), or must be identified as new neurons in these two articles. We compared the interaction between these two neural substrates (2) to the conditioning paradigm of the other animals (12)(13)(14) and to that of the intact earthworm (15,16).…”

Section: Introductionmentioning

confidence: 99%

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Identification of the main generator source of longitudinal muscle contraction in the earthworm ventral nerve cord

Chang

Assmé

Caffaro

et al. 1998

Braz J Med Biol Res

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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% of the amplitude, 73% of the rising rate and 81% of the duration of a longitudinal muscle contraction recorded by a mechanoelectrical 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.

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Section: Synaptic Connection Between the Main Generator Neuronsmentioning

confidence: 96%