Observations on the organization of the dendritic processes and receptor terminations in the abdominal muscle receptor organ of homarus

1969 ◽  
Vol 137 (1) ◽  
pp. 19-57 ◽  
Author(s):  
Joseph B. Nadol ◽  
A. J. Darin de Lorenzo
Keyword(s):  
Abdominal Muscle ◽  
Muscle Receptor ◽  
Receptor Organ

scholarly journals Abdominal postural motor responses initiated by the muscle receptor organ in lobster depend upon centrally generated motor activity

1992 ◽  
Vol 162 (1) ◽  
pp. 167-183
Author(s):  
S. C. Sukhdeo ◽  
C. H. Page
Keyword(s):  
Motor Activity ◽  
Motor Neurons ◽  
Procambarus Clarkii ◽  
Homarus Americanus ◽  
Abdominal Muscle ◽  
Sensory Response ◽  
Reflex Responses ◽  
Muscle Receptor ◽  
Postural Reflex ◽  
Receptor Organ

1. Stretch stimulation of the abdominal muscle receptor organ of the lobster Homarus americanus initiated spike discharge of its tonic sensory neuron (SR1). This sensory response evoked a series of tonic postural reflex responses in the motor neurons that innervate the superficial extensor and flexor muscles of the abdominal postural system. The type of motor response depended on whether a flexion or extension pattern of spontaneous activity was being generated by the postural efferents. Spontaneous shifts between these centrally generated motor activities completely changed the SR1-evoked reflex responses. 2. During spontaneous centrally initiated flexion activity, tonic SR1 neuron discharge elicited an assistance response that included excitation of a medium-sized flexor excitor (f3) and the peripheral extensor inhibitor (e5), and inhibition of at least one extensor excitor. Neither the other flexor excitors nor the peripheral flexor inhibitor (f5) were affected by SR1 excitation. 3. During spontaneous centrally initiated extension activity, SR1 activity elicited a response that included excitation of the extensor excitors and the flexor peripheral inhibitor (f5) only, f3 and e5 spontaneous activities were unchanged. This response was a resistance reflex, since SR1 discharge normally resulted from an imposed abdominal flexion. 4. The SR1-initiated control of postural motor activity in lobster differs from previously published results in the crayfish Procambarus clarkii.

The role of the muscle receptor organ in the control of abdominal extension in the crayfish, Cherax destructor

1995 ◽  
Vol 198 (11) ◽  
pp. 2253-2259 ◽  
Author(s):  
B Mccarthy ◽  
D Macmillan
Keyword(s):  
Constant Load ◽  
Abdominal Muscle ◽  
Muscle Receptor ◽  
Complete Extension ◽  
Cherax Destructor ◽  
Before And After ◽  
Error Detector ◽  
Receptor Organ ◽  
Servo Loop

A platform was lowered from beneath suspended crayfish, Cherax destructor, to evoke slow abdominal extension. The movements were filmed and the length between segments plotted as a function of time. Unlike abdominal flexion, which starts posteriorly and progresses anteriorly, extension occurs at all joints simultaneously. Although the duration of extension varied from trial to trial for an individual, the movement was organised in a stereotyped manner: the abdomen achieved a consistent position for any given proportion of the time for complete extension. We examined the role of the abdominal muscle receptor organs (MROs) in extension by cutting the nerves of selected MROs to abolish their input. The extension movement was measured before and after nerve section for animals with either unloaded or loaded abdomens. Removal of MRO input had no significant effect on extension of the unloaded abdomen. In animals with a loaded abdomen, the extension at joints spanned by sectioned MROs was slowed, whereas that at joints with intact MROs was not. The findings are consistent with the hypothesis that the MRO is an error detector in a servo-loop controlling abdominal position. The results provide the first demonstration that this load-compensating reflex loop operates during naturally evoked extension of the abdomen under constant load.

A new muscle receptor organ in the antenna of the rock lobster Palinurus vulgaris : mechanical, muscular and proprioceptive organization of the two proximal joints J0 and J1

1983 ◽  
Vol 218 (1210) ◽  
pp. 95-110 ◽  
Keyword(s):  
Anterior Part ◽  
Proximal Part ◽  
The Other ◽  
Chordotonal Organ ◽  
Excitatory Postsynaptic Potentials ◽  
Rock Lobster ◽  
Postsynaptic Potentials ◽  
Muscle Receptor ◽  
Physiological Properties ◽  
Receptor Organ

(i) Following previous work on the morphological and physiological properties of the two distal joints (J2, J3) of the atenna of the rock lobster Palinurus vulgaris , the mechanical, muscular and proprioceptive organization of the two proximal joints between the antennal segments S1 and S2 (J1) and between S1 and the cephalothorax (J0) have now been studied. (ii) Articulated by two classical condyles, J1 moves in a mediolateral plane. One external rotator muscle (ER) and three internal rotator muscles (IR1, IR2, IR3) subserve its movements. J0 is articulated by two different systems: a classical ventrolateral condyle and a complex sliding system constituted by special cuticular structures on the dorsomedial side of the S1 segment and on the rostrum between the two antennae. J0 moves in the dorsoventral plane by means of a levator muscle (Lm) and a depressor muscle (Dm). A third muscle, the lateral tractor muscle (LTm), associated with J0 and lying obliquely across S1, may modulate the level of friction between the S1 segment and the rostrum. (iii) Proprioception in J1 is achieved by a muscle receptor organ AMCO-J1 (antennal myochordotonal organ for the J1 joint) associating a small accessory muscle (S1.am) located in the proximal part of the S1 segment and a chordotonal organ inserted proximally on the S1.am muscle and distally on the S2 segment. J0 proprioception is ensured by a simple chordotonal organ (CO-J0) located in the anterior part of the cephalothorax. (iv) The S1.am muscle is innervated by three motoneurons characterized by their very small diameters and inducing respectively tonic excitatory postsynaptic potentials, phasic excitatory postsynaptic potentials and inhibitory postsynaptic potentials. Anatomical and physiological observations suggest functional correlation between S1.am and IR1 motor innervation. (v) Mechanical and muscular organization of J0 and J1 are compared with that of the other joints of the antenna. The properties of the AMCO-J1 proprioceptor are discussed in relation to the other muscle receptor organs described in crustaceans.

A muscle receptor organ in the scorpion postabdomen

1972 ◽  
Vol 81 (2) ◽  
pp. 133-146 ◽  
Author(s):  
Robert F. Bowerman
Keyword(s):  
Muscle Receptor ◽  
Receptor Organ

Phase-dependent reversal of reflexes mediated by the thoracocoxal muscle receptor organ in the crayfish, Pacifastacus leniusculus

1986 ◽  
Vol 55 (4) ◽  
pp. 689-695 ◽  
Author(s):  
P. Skorupski ◽  
K. T. Sillar
Keyword(s):  
Motor Neurons ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Motor Output ◽  
Dependent Manner ◽  
Muscle Receptor ◽  
Reflex Pathways ◽  
Receptor Organ ◽  
Positive And Negative Feedback ◽  
Central Excitability

Both negative feedback, resistance reflexes and positive feedback, assistance reflexes are mediated by the thoracocoxal muscle receptor organ (TCMRO) in the crayfish, depending on the central excitability of the preparation. In this paper we present evidence that the velocity-sensitive afferent T fiber of the TCMRO may elicit either resistance or assistance reflexes in different preparations. In preparations displaying assistance reflexes, the S and T fibers of the TCMRO exert reciprocal effects on leg motor neurons (MNs). The S fiber excites promotor MNs (negative feedback) and inhibits remotor MNs, the T fiber excites remotor MNs (positive feedback) and inhibits promotor MNs. During reciprocal motor output of promotor and remotor MNs, reflexes mediated by the TCMRO are modulated in a phase-dependent manner. The TCMRO excites promotor MNs during their active phases (negative feedback) but inhibits them during their reciprocal phases. Remotor MNs are excited by the TCMRO during their active phases (positive feedback). It is proposed that depolarizing central inputs that occur in the S and T fibers at opposite phases of the motor output cycle (21) facilitate the output effects of each afferent in alternation, effectively mediating a phase-dependent shift between the effects of one afferent and the other. The implications of central modulation of reflex pathways and the possible functions of positive and negative feedback reflexes during locomotion are discussed.

Effect of nicotine and acetylcholine on crustacean muscle membrane potential

1986 ◽  
Vol 61 (2) ◽  
pp. 807-809
Author(s):  
R. F. Taylor ◽  
D. T. Frazier
Keyword(s):  
Membrane Potential ◽  
Muscle Tension ◽  
Muscle Cells ◽  
Abdominal Muscle ◽  
Muscle Membrane ◽  
Resting Membrane Potential ◽  
Crustacean Muscle ◽  
Standard Glass ◽  
Before And After ◽  
Receptor Organ

We have investigated the effect of nicotine and acetylcholine on the resting membrane potential of the crayfish extensor muscle in order to determine whether crustacean muscle can be activated by cholinergic compounds. Intracellular recordings from individual deep extensor abdominal muscle cells were made using standard glass microelectrode techniques. The resting membrane potential was measured before and after treatment with glutamate, nicotine, and acetylcholine. Glutamate, which is a known activator of crayfish muscle, was used to determine whether the muscle cell preparation was viable and capable of responding to any of the test substances. Our results confirm that application of glutamate is associated with a depolarization of the muscle membrane. However, muscle cells showed no depolarization after treatment with nicotine (50 microM) or acetylcholine (66 microM). These results argue against the notion that increases in muscle tension may be responsible for the increased receptor organ discharge observed in the presence of nicotine. Rather, it supports the hypothesis that nicotine is acting directly on the mechanoreceptor membrane to change its sensitivity.

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