Effects of scaphognathite nerve stimulation on the acutely deafferented crab ventilatory central pattern generator

Wilkens, J. L.; DiCaprio, Ralph A.

doi:10.1007/bf00193786

Cited by 5 publications

(17 citation statements)

References 31 publications

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“…The semi-isolated thoracic ganglion containing the two ventilatory CPG~s was prepared after the method of Simmers and Bush (1983) and as outlined in Wilkens and DiCaprio (1994). All experiments were performed at room temperature (20-22~ Physiological recording and stimulation.…”

Section: Methodsmentioning

confidence: 99%

“…All experiments were performed at room temperature (20-22~ Physiological recording and stimulation. All recording and stimulation conditions were identical to those previously outlined (Wilkens and DiCaprio 1994).…”

Section: Methodsmentioning

confidence: 99%

“…Phase response curves were constructed to evaluate the effects on the CPG v of brief trains of stimuli applied to either the levator (LN) or depressor (DN) nerves. The ability of trains of stimuli to entrain the CPGv rhythm was also evaluated as previously described (Wilkens and DiCaprio 1994).…”

Section: Methodsmentioning

confidence: 99%

“…A neuron is considered to be part of the CPG proper if its artificial depolarization or hyperpolarization can reset the phasing of the rhythm (Moffett 1977). Recently it has become apparent that the concept of the CPG in some cases must be restricted since sensory feedback is necessary for the actual pattern generated (PG) by the intact animal (B/issler 1986a, b;Pearson and Wolf 1987;Pearson 1987 1989) and since stimulation of afferents can reset some rhythms (Wendler 1974;Young and Coyer 1979;Wilkens and DiCaprio 1994).…”

Section: Introductionmentioning

confidence: 99%

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Degeneration of afferent neurons and long-term stability of the ventilatory central pattern generator in chronically deafferented crabs

Wilkens

1994

J Comp Physiol A

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1. The effects of chronic deafferentation, 3-180 days, are tested on the function and morphology of the crab (Carcinus maenas) ventilatory central pattern generator (CPGv). Almost all afferent axons are carried in the mixed sensory/motor levator nerve. The ability to speed the CPGv cycle rate by stimulating this nerve (Wilkens and DiCaprio 1994) decreases as the afferent neurons degenerate. Stimulation of the levator nerve eliminates motor units from the output even after 60 days of deafferentation, similar to the effects seen in acute preparations.2. The 3 oval organ afferent axons of the levator nerve have central somata and survive scaphognathectomy. Impulses carried by these axons are known to inhibit the CPG v in acutely deafferented preparations and they are believed to be responsible for the persistent inhibition following small afferent degeneration seen here.3. After 6 months of deafferentation the motor neuron collateral arborization densities within the thoracic ganglia are reduced, but all motor neurons appear to survive. These long-term deafferented CPG~s generate accurate motor patterns at similar rates to the control CPG~, but at reduced intraburst spike frequency. The crab CPGv is quite stable following chronic deafferentation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Degeneration of afferent neurons and long-term stability of the ventilatory central pattern generator in chronically deafferented crabs

Wilkens

1994

J Comp Physiol A

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“…Wood and Randall (1981) postulated for the crab Cardisoma carnifex the presence of a feedback arc from putative proprioceptors in the limbs to the respiratory organ, the scaphognathite. Wilkens and DiCaprio (1994) showed the presence of reflex neural circuits between the scaphognathites arid the CNS. Burggren et al (1990) have presented evidence for baroreflex regulation of the heart of Cardisoma guanhumi in response to artificially-produced changes of haemolymph volume.…”

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confidence: 98%

Neural mechanisms governing distribution of cardiac output in an isopod crustacean, Bathynomus doederleini: reflexes controlling the cardioarterial valves

Okada

Kuwasawa

1995

J Comp Physiol A

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In Bathynomus doederleini all of the cardioarterial valves located at the origin of the lateral arteries are dilated by impulses of lateral cardiac nerves. Tactile stimuli applied to sensillar setae depress impulse activities of the 1st and 5th lateral cardiac nerves. The 1st lateral cardiac nerve controls the valve of the lateral artery which runs to the walking-legs and viscera. The 5th lateral cardiac nerve controls the valve of the lateral artery which runs to the swimmeret muscles. The response indicates that tactile receptor reflexes bring about decreased haemolymph flow to the organs. Augmented swimmeret movements were always accompanied by an increased firing rate in the 5th lateral cardiac nerve. Artificial full protraction of swimmerets simultaneously induced excitation of the 5th lateral cardiac nerve and inhibition of the 1st lateral cardiac nerve. The excitation corresponds to an increase in haemolymph flow to the swimmerets, and the inhibition a decrease in haemolymph flow to walking-legs and viscera. Three kinds of mechanoproprioceptors which were activated by swimmeret movements were found. Two of the mechanoproprioceptors are located at the base of the basipodite. The other mechanoproprioceptor supplies processes to a nerve to the retractor muscles. Activation of three kinds of mechanoproprioceptors, induced by artificial swimmeret protraction, triggered lateral cardiac nerve reflex responses.Key words Cardioarterial valve -Valve dilator nerve 9 Haemolymph distribution 9 Mechanoproprioceptor 9 Mechanosensory reflexes Abbreviations LA lateral artery" LCNlateral cardiac nerve. RMNnerve to retractor muscles. StRstretch receptor

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Blockade of the central generator of locomotor rhythm by noncompetitive NMDA receptor antagonists in Drosophila larvae

Cattaert

Birman

2001

J. Neurobiol.

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The noncompetitive antagonists of the vertebrate N-methyl-D-aspartate (NMDA) receptor dizocilpine (MK 801) and phencyclidine (PCP), delivered in food, were found to induce a marked and reversible inhibition of locomotor activity in Drosophila melanogaster larvae. To determine the site of action of these antagonists, we used an in vitro preparation of the Drosophila third-instar larva, preserving the central nervous system and segmental nerves with their connections to muscle fibers of the body wall. Intracellular recordings were made from ventral muscle fibers 6 and 7 in the abdominal segments. In most larvae, long-lasting (>1 h) spontaneous rhythmic motor activities were recorded in the absence of pharmacological activation. After sectioning of the connections between the brain and abdominal ganglia, the rhythm disappeared, but it could be partially restored by perfusing the muscarinic agonist oxotremorine, indicating that the activity was generated in the ventral nerve cord. MK 801 and PCP rapidly and efficiently inhibited the locomotor rhythm in a dose-dependent manner, the rhythm being totally blocked in 2 min with doses over 0.1 mg/mL. In contrast, more hydrophilic competitive NMDA antagonists had no effect on the motor rhythm in this preparation. MK 801 did not affect neuromuscular glutamatergic transmission at similar doses, as demonstrated by monitoring the responses elicited by electrical stimulation of the motor nerve or pressure applied glutamate. The presence of oxotremorine did not prevent the blocking effect of MK 801. These results show that MK 801 and PCP specifically inhibit centrally generated rhythmic activity in Drosophila, and suggest a possible role for NMDA-like receptors in locomotor rhythm control in the insect CNS.

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Effects of scaphognathite nerve stimulation on the acutely deafferented crab ventilatory central pattern generator

Cited by 5 publications

References 31 publications

Degeneration of afferent neurons and long-term stability of the ventilatory central pattern generator in chronically deafferented crabs

Degeneration of afferent neurons and long-term stability of the ventilatory central pattern generator in chronically deafferented crabs

Neural mechanisms governing distribution of cardiac output in an isopod crustacean, Bathynomus doederleini: reflexes controlling the cardioarterial valves

Blockade of the central generator of locomotor rhythm by noncompetitive NMDA receptor antagonists in Drosophila larvae

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