Inhibitory Control of the Abdominal Stretch Receptors of the Crayfish (original) (raw)
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Reflex Inhibition of the Slowly Adapting Stretch Receptors in the Intact Abdomen of the Crayfish
Acta Physiologica Scandinavica, 1975
NJA, A. and L. WALL0E. Reflex inhibition of the slowly adapting stretch receptors in the intact abdomen of' the crayfish. Acta physiol. scand. 1975. 94. 177-183. The reflex inhibition of abdominal stretch receptors in crayfish was studied by controlled passive flexion of individual abdominal joints. The results are very similar to those obtained by electrical or mechanical stimulation of individual stretch receptors in immobilized abdomens. Reflex effects from posterior to anterior abdominal segments are somewhat stronger than in the opposite direction. Flexion of one abdominal joint excites the stretch receptors of that joint and inhibits the stretch receptors in neighbouring abdominal segments. Without reflex inhibition flexion of one abdominal joint excites the stretch receptors in several abdominal segments.
Structure and function relationship in the abdominal stretch receptor organs of the crayfish
The Journal of Comparative Neurology, 2005
The structure/function relationship in the rapidly and slowly adapting stretch receptor organs of the crayfish (Astacus leptodactylus) was investigated using confocal microscopy and neuronal modeling methods. Both receptor muscles were single muscle fibers with structural properties closely related to the function of the receptors. Dendrites of the rapidly adapting neuron terminated in a common pile of nerve endings going in all directions. Dendrites of the slowly adapting neuron terminated in a characteristic T shape in multiple regions of the receptor muscle. The slowly adapting main dendrite, which was on average 2.1 times longer and 21% thinner than the rapidly adapting main dendrite, induced larger voltage attenuation. The somal surface area of the slowly adapting neuron was on average 51% larger than that of the rapidly adapting neuron. Variation in the neuronal geometry was greatest among the slowly adapting neurons. A computational model of a neuron pair demonstrated that the rapidly and the slowly adapting neurons attenuated the dendritic receptor potential like low-pass filters with cutoff frequencies at 100 and 20 Hz, respectively. Recurrent dendrites were observed mostly in the slowly adapting neurons. Voltage signals were calculated to be propagated 23% faster in the rapidly adapting axon, which is 51% thicker than the slowly adapting axon. The present findings support the idea that the morphology of the rapidly and the slowly adapting neurons evolved to optimally sense the dynamic and the static features of the mechanical stimulus, respectively.
Biochemical Pharmacology, 1964
A radioautographic technique was developed by which it was possible to visua1iz.e y-aminobutyric acid frABA) that was bound to isolated abdominal stretch receptors of the crayfish during brief incubation in a suitable salt solution containing yABASH of high specific activity. The binding, which takes place even at 0 to 4", was enhanced at room temperature. The pattern of labeling was found to be consistent with a greater degree of focalization than elsewhere at the axodendritic endings between branches of the inhibitory axon and the dendrites of the sensory neuron. Neither thym~dine-3H nor Dt,-leucine-3H showed a simitar pattern. The characteristic binding of rAI3A by the stretch receptors was disrupted by distilled water, formalin, or by employing a Na+-free saline.
Transfer properties of the slowly adapting stretch receptor of the crayfish abdomen
Acta Physiologica Scandinavica, 1980
The slowly adapting stretch receptor in the abdomen of freshwater crayfish (Astacus fluviatilis) was investigated to determine its properties under dynamic conditions. An in situ preparation was used; the necessary dissection did not involve the receptor organ or its immediate surroundings. Sinusoidal variations in the angle of flexion in the joint to which the receptor organ was connected, were generated by a feed-back controlled stretcher. Nerve spikes recorded from the axon of the receptor neurone and information about angle of flexion in the joint obtained by position transducers, were fed into a computer. Fourier transforms were performed on both input and output data to determine the amplitude of the 0. and I. harmonic together with the phase of the 1. harmonic. The receptor organ was investigated for linearity up to 1.5 degrees input amplitude, and proved to be surprisingly linear within this range. In addition. the transfer function of the receptor organ was determined by stimulating it with small-amplitude sinusoidals with different frequencies.
General physiology and biophysics, 2002
Action potentials (APs) and impulse responses in the soma and axon of the rapidly and slowly adapting (SA) abdominal stretch receptor neurons of the crayfish (Astacus leptodactylus) were recorded with single microelectrode current-clamp technique. Impulse frequency response to constant current injection was almost constant in the SA neuron while the response decayed completely in the rapidly adapting (RA) neuron. Mean impulse frequency responses to current stimulations were similar in the receptor neuron pairs. In the RA neuron additional current steps evoked additional impulses while a sudden drop in the current amplitude caused adaptation. Impulse duration was dependent on the rate of rise when current ramps were used. Adaptation was facilitated when calculated receptor current was used. Exposing the neuron to 3 mmol/l TEA or scorpion venom resulted in partly elongated impulse responses. SA neuron could continuously convert the current input into impulse frequency irrespective of ...