PROPRIOCEPTIVE INPUT FROM TWO BASAL JOINT STRETCH RECEPTORS TO LEG MOTONEURONES IN THE ISOLATED THORACIC GANGLION OF THE SHORE CRAB

1992 ◽  
Vol 163 (1) ◽  
pp. 187-208
Author(s):  
STEWART I. HEAD ◽  
BRIAN M.H. BUSH
Keyword(s):  
Motor Nerve ◽  
Carcinus Maenas ◽  
Thoracic Ganglion ◽  
Shore Crab ◽  
Chordotonal Organ ◽  
Leg Muscles ◽  
Receptor Organ ◽  
Motor Nerves

The reflex effects and interactions of two proprioceptors upon motoneurones supplying the four basal leg muscles of the shore crab Carcinus maenas have been studied in a new in vitro preparation consisting of the thoracic-coxal muscle receptor organ (TCMRO) and the coxo-basal chordotonal organ (CBCO) isolated together with the whole thoracic ganglion complex to which they were still connected by their afferent nerves. Each receptor strand was stimulated mechanically, while recording intracellularly from motoneurones in the ganglion, and extracellularly from the cut motor nerves innervating the promotor and remotor muscles of the thoracic-coxal (T—C) joint and the levator and depressor muscles of the coxo-basal (C—B) joint. Stretch of the TCMRO evoked reflex firing in several units in the promotor motor nerve, confirming previous studies. In addition to this ‘intrajoint’ reflex, however, TCMRO stretch also elicited ‘interjoint’ reflex responses in motoneurones of both the levator and depressor muscles. Similarly, stretch and release of the CBCO produced intrajoint resistance reflexes in levator and depressor motoneurones, respectively, as well as interjoint reflexes in promotor and remotor motoneurones. In general, the CBCO produced stronger reflex effects in all four motor nerves than did the TCMRO. Intracellular recordings from individual motoneurones of all four muscles revealed that the majority of them received convergent input from both proprioceptors. The importance of such convergent input in vivo is discussed

The Uptake of Cadmium Into the Haemolymph of the Shore Crab Carcinus Maenas: The Relationship With Copper and Other Divalent Cations

1977 ◽  
Vol 67 (1) ◽  
pp. 147-161
Author(s):  
D. A. WRIGHT
Keyword(s):  
Divalent Cations ◽  
Cadmium Concentration ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Cadmium Level ◽  
Haemolymph Protein ◽  
Urine Cadmium ◽  
The Relationship

When Carcinus was exposed to 20 μ-mol l−1 cadmium, the haemolymph cadmium level was initially dependent upon the salinity of the external medium. After 14 days the mean haemolymph cadmium level in 50% s.w. animals was nearly twice that of 100% s.w. animals. This trend was not sustained, however, and the situation was complicated by occasional inconsistent values. In both in vivo and in vitro conditions nearly all the haemolymph cadmium becomes bound to haemolymph protein within a few days. The relationship between haemolymph cadmium, copper and protein concentration has been investigated. Although the latter are highly correlated with each other, cadmium formed a significant positive relationship with haemolymph copper (r = 0.523) and protein (r = 0.533) only after 3–4 weeks uptake. Exposure to 20 μ-mol l−1 cadmium has no obvious effects on haemolymph protein and copper concentrations, which are clearly dependent on feeding status. Mortalities among experimental animals were often preceded by a rise in haemolymph cadmium concentration. This is usually seen before there are any obvious signs of tissue breakdown. Urine cadmium loss is probably unimportant as a pathway for the elimination of this metal. Urine cadmium concentrations often exceeded serum cadmium levels indicating that cadmium may sometimes be eliminated in bound form.

scholarly journals Crustacean hyperglycaemic hormone (CHH)-like peptides and CHH-precursor-related peptides from pericardial organ neurosecretory cells in the shore crab, Carcinus maenas, are putatively spliced and modified products of multiple genes

2001 ◽  
Vol 356 (1) ◽  
pp. 159-170 ◽  
Author(s):  
Heinrich DIRCKSEN ◽  
Detlef BÖCKING ◽  
Uwe HEYN ◽  
Christa MANDEL ◽  
J. Sook CHUNG ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Carcinus Maenas ◽  
Penaeid Shrimp ◽  
Neurosecretory Cells ◽  
Shore Crab ◽  
Amino Acid Peptide ◽  
C Terminus ◽  
Gene Structures

About 24 intrinsic neurosecretory neurons within the pericardial organs (POs) of the crab Carcinus maenas produce a novel crustacean hyperglycaemic hormone (CHH)-like peptide (PO-CHH) and two CHH-precursor-related peptides (PO-CPRP I and II) as identified immunochemically and by peptide chemistry. Edman sequencing and MS revealed PO-CHH as a 73 amino acid peptide (8630Da) with a free C-terminus. PO-CHH and sinus gland CHH (SG-CHH) share an identical N-terminal sequence, positions 1–40, but the remaining sequence, positions 41–73 or 41–72, differs considerably. PO-CHH may have different precursors, as cDNA cloning of PO-derived mRNAs has revealed several similar forms, one exactly encoding the peptide. All PO-CHH cDNAs contain a nucleotide stretch coding for the SG-CHH41–76 sequence in the 3′-untranslated region (UTR). Cloning of crab testis genomic DNA revealed at least four CHH genes, the structure of which suggest that PO-CHH and SG-CHH arise by alternative splicing of precursors and possibly post-transcriptional modification of PO-CHH. The genes encode four exons, separated by three variable introns, encoding part of a signal peptide (exon I), the remaining signal peptide residues, a CPRP, the PO-CHH1–40/SG-CHH1–40 sequences (exon II), the remaining PO-CHH residues (exon III) and the remaining SG-CHH residues and a 3′-UTR (exon IV). Precursor and gene structures are more closely related to those encoding related insect ion-transport peptides than to penaeid shrimp CHH genes. PO-CHH neither exhibits hyperglycaemic activity in vivo, nor does it inhibit Y-organ ecdysteroid synthesis in vitro. From the morphology of the neurons it seems likely that novel functions remain to be discovered.

Reflexes Mediated by Non-Impulsive Afferent Neurones of Thoracic-Coxal Muscle Receptor Organs in the Crab, Carcinus Maenas: I. Receptor Potentials and Promotor Motoneurone Responses

1980 ◽  
Vol 86 (1) ◽  
pp. 275-303
Author(s):  
A. J. CANNONE ◽  
B. M. H. BUSH
Keyword(s):  
Carcinus Maenas ◽  
Receptor Potential ◽  
Reflex Response ◽  
Shore Crab ◽  
Sensory Fibre ◽  
Muscle Receptor ◽  
Receptor Organ ◽  
Length Changes ◽  
Receptor Muscle

Address for reprints. 1. A preparation of the thoracic-coxal muscle receptor organ of the posterior leg of the shore crab, in which central synaptic efficacy of the sensori-motor reflex pathways is maintained for long periods, is described. 2. The reflex response to receptor muscle stretch commonly involves three promotor motoneurones, designated Pm1-3 in order of their recruitment. 3. Motoneurone Pm1, and less frequently Pm2 and Pm3, may be tonically active during maintained receptor length changes within the in situ length range of the receptor muscle. 4. The following observations suggest that the T rather than the S sensory fibre provides the afferent drive onto reflexly activated promotor motoneurones: selective section of the S or T sensory fibres; frequency ‘envelopes’ of individual motoneurone responses to trapezoid stretch stimuli, including features such as adaptation and velocity sensitivity of the reflex response; and the ‘hysteresis’ in the response to increasing followed by decreasing receptor length changes, with or without superimposed trapezoid stretch stimuli. 5. The initial reflex response to ramp stretch can be directly related to the complex ‘initial component’ of the T fibre receptor potential waveform. This comprises a variable spiky alpha (α) component, followed by a longer duration, more predictable beta (β) component, which depends upon stimulus parameters such as stretch velocity and the length and tension of the receptor muscle at the onset of stretch. 6. In the de-efferented receptor muscle, changes in compliance or ‘tonus’ resulting from receptor manipulation have a marked effect on the sensory, and hence reflex, response to stretch. As this would have profound implications for the functioning of this muscle receptor organ in vivo, a role for the receptor motor innervation in counteracting any such response variability seems likely.

Host Defence Reactions of the Shore Crab, Carcinus Maenas (L.): Clearance and Distribution of Injected Test Particles

1980 ◽  
Vol 60 (1) ◽  
pp. 89-102 ◽  
Author(s):  
Valerie J. Smith ◽  
N. A. Ratcliffe
Keyword(s):  
Specific Activity ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Foreign Material ◽  
Defence Mechanisms ◽  
Test Particles ◽  
Cellular Defence ◽  
Defence Reactions

It is well established that crustaceans can overcome infection and clear foreign material introduced into the circulation (Cornick & Stewart, 1968; Tyson & Jenkin, 1973; Stewart & Zwicker, 1974). In the absence of vertebrate-type specific acquired immunity, the non-specific activity mediated by the circulating blood cells appears to be of considerable importance in resistance to disease (Sindermann, 1971). Among the cellular defence mechanisms of the Crustacea, phagocytosis has received most attention and there is considerable evidence from in vitro studies that this process plays an important part in the removal of foreign particles from the blood (McKay & Jenkin, 1970a; Paterson & Stewart, 1974; Tyson & Jenkin, 1974; Paterson, Stewart & Zwicker, 1976; Smith & Ratcliffe, 1978). Such studies, however, may not always reflect the true in vivo condition, and there is a great need for correlated in vitro and in vivo investigations.

scholarly journals Motor Nerve Regeneration Using an Optimized Nerve Allograft in a Rat Model - An In vitro and In vivo Analysis

2015 ◽  
Vol 40 (9) ◽  
pp. e35
Author(s):  
Caroline A. Hundepool ◽  
Liselotte F. Bulstra ◽  
Dimitra Kotsougiani ◽  
Steven Hovius ◽  
Allen Bishop ◽  
...  
Keyword(s):  
Nerve Regeneration ◽  
Rat Model ◽  
Motor Nerve ◽  
In Vivo Analysis

INTEGRATION OF POSITIVE AND NEGATIVE FEEDBACK LOOPS IN A CRAYFISH MUSCLE

1994 ◽  
Vol 187 (1) ◽  
pp. 305-313
Author(s):  
P Skorupski ◽  
P Vescovi ◽  
B Bush
Keyword(s):  
Negative Feedback ◽  
Positive Feedback ◽  
Motor Neurone ◽  
Chordotonal Organ ◽  
Negative Feedback Loops ◽  
Reflex Pathways ◽  
Motor Neurones ◽  
Receptor Organ ◽  
Group 2

It is now well established that in arthropods movement-related feedback may produce positive, as well as negative, feedback reflexes (Bassler, 1976; DiCaprio and Clarac, 1981; Skorupski and Sillar, 1986; Skorupski et al. 1992; Vedel, 1980; Zill, 1985). Usually the same motor neurones are involved in both negative feedback (resistance) reflex responses and positive feedback reflexes. Reflex reversal involves a shift in the pattern of central inputs to a motor neurone, for example from excitation to inhibition. In the crayfish, central modulation of reflexes has been described in some detail for two basal limb proprioceptors, the thoracocoxal muscle receptor organ (TCMRO) and the thoracocoxal chordotonal organ (TCCO) (Skorupski et al. 1992; Skorupski and Bush, 1992). Leg promotor motor neurones are excited by stretch of the TCMRO (which, in vivo, occurs on leg remotion) in a negative feedback reflex, but when this reflex reverses they are inhibited by the same stimulus. Release of the TCCO (which corresponds to leg promotion) excites some, but not all, promotor motor neurones in a positive feedback reflex. There are at least two ways in which the reflex control of a muscle may be modulated in this system. Firstly, inputs to motor neurones may be routed via alternative reflex pathways to produce different reflex outputs. Secondly, the pattern of inputs to a motor pool may be inhomogeneous, so that activation of different subgroups of the motor pool causes different outputs. Different crayfish promotor motor neurones are involved in different reflexes. On this basis, the motor neurones may be classified into at least two subgroups: those that are excited by the TCCO in a positive feedback reflex (group 1) and those that are not (group 2). Do these motor neurone subgroups have different effects on the promotor muscle, or is the output of the two promotor subgroups summed at the neuromuscular level? To address this question we recorded from the promotor nerve and muscle in a semi-intact preparation of the crayfish, Pacifastacus leniusculus. Adult male and female crayfish, 8-11 cm rostrum to tail, were decapitated and the tail, carapace and viscera removed. The sternal artery was cannulated and perfused with oxygenated crayfish saline, as described previously (Sillar and Skorupski, 1986).

Sensory feedback and central afferent interaction in the muscle receptor organ of the crab, Carcinus maenas

1996 ◽  
Vol 76 (2) ◽  
pp. 788-798 ◽  
Author(s):  
M. Wildman ◽  
A. Cannone
Keyword(s):  
Action Potentials ◽  
Sensory Feedback ◽  
Carcinus Maenas ◽  
Small Diameter ◽  
Sensory Response ◽  
Fiber Direction ◽  
Single Action ◽  
Muscle Receptor ◽  
Leg Muscles ◽  
Receptor Organ

1. An interaction exists between two proprioceptive afferent neurons innervating the thoracic-coxal muscle receptor organ (TCMRO) of the crab, Carcinus maenas. Intracellular recordings were made from the extraganglionic regions of the afferents in order to characterize this interaction and its effects on sensory feedback. 2. A current-induced depolarization of the nonspiking T fiber of the TCMRO results in a depolarization of the P fiber, a small-diameter (7 microns) neuron innervating the same receptor. This interaction is graded in amplitude, and may result in a single action potential being superimposed on the graded response of the P fiber. A hyperpolarization of the T fiber has a smaller effect on the P fiber than a depolarization of similar amplitude. The interaction is rectified in a T- to P-fiber direction, and has a minimum central delay of approximately 3.6 ms. 3. The site of the interaction between the afferents is situated centrally, within the thoracic ganglion. Action potentials evoked in the P fiber by a T-fiber depolarization propagate actively and antidromically to the periphery. 4. Central modulation of the interaction occurs, because the amplitude of a T-fiber-induced depolarization is reduced in the P fiber during centrally generated spontaneous bursts of activity in the motoneurons of basal leg muscles. 5. Because of the interaction between T and P fibers, action potentials recorded from the peripheral portion of the P fiber during receptor stretch may be either orthodromic, resulting directly from the effects of the stretch on the sensory endings of the P fiber, or antidromic, resulting from the central input from the T fiber. 6. The T- to P-fiber interaction may serve to extend the dynamic sensitivity range of the P fiber, in particular by amplifying its sensory response at short receptor lengths and low velocities of stretch.

Sign in / Sign up

Export Citation Format

Share Document