Elasticity, unexpected contractility and the identification of actin and myosin in lobster arteries

Wilkens, J. L.; Cavey, Michael J.; Shovkivska, Iryna; Zhang, M. L.; Keurs, H. E. D. J. ter

doi:10.1242/jeb.007658

Cited by 15 publications

(19 citation statements)

References 32 publications

(46 reference statements)

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“…Several of these same modulators, including proctolin (Wilkens et al, 2005), and a number of different FMRFamide-like peptides (Fort et al, 2007a;Stevens et al, 2009;Wilkens et al, 2005), also exert effects at the neuromuscular junction or directly on crustacean cardiac muscle. Some have likewise been shown to affect other aspects of the circulatory system, including blood vessels and vascular resistance (Wilkens et al, 2008;Wilkens and Taylor, 2003). Moreover, several recent studies have shown that the effects of the same modulator differ either quantitatively or qualitatively when applied to the semi-intact heart and the isolated CG (Fort et al, 2004;Fort et al, 2007a;Fort et al, 2007b;Stevens et al, 2008;Stevens et al, 2009), suggesting the possibility that these modulators exert effects at other sites, potentially including feedback pathways within the cardiac neuromuscular system.…”

Section: Discussionmentioning

confidence: 99%

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus

Wiwatpanit

Powers

Dickinson

2012

Journal of Experimental Biology

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SUMMARYAlthough the global effects of many modulators on pattern generators are relatively consistent among preparations, modulators can induce different alterations in different preparations. We examined the mechanisms that underlie such variability in the modulatory effects of the peptide C-type allatostatin (C-AST; pQIRYHQCYFNPISCF) on the cardiac neuromuscular system of the lobster Homarus americanus. Perfusion of C-AST through the semi-intact heart consistently decreased the frequency of ongoing contractions. However, the effect of C-AST on contraction amplitude varied between preparations, decreasing in some preparations and increasing in others. To investigate this variable effect, we examined the effects of C-AST both peripherally and centrally. When contractions of the myocardium were elicited by controlled stimuli, C-AST did not alter heart contraction at the periphery (myocardium or neuromuscular junction) in any hearts. However, when applied either to the semi-intact heart or to the cardiac ganglion (CG) isolated from hearts that responded to C-AST with increased contraction force, C-AST increased both motor neuron burst duration and the number of spikes per burst by about 25%. In contrast, CG output was increased only marginally in hearts that responded to C-AST with a decrease in contraction amplitude, suggesting that the decrease in amplitude in those preparations resulted from decreased peripheral facilitation. Our data suggest that the differential effects of a single peptide on the cardiac neuromuscular system are due solely to differential effects of the peptide on the pattern generator; the extent to which the peptide induces increased burst duration is crucial in determining its overall effect on the system.

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Section: Discussionmentioning

confidence: 99%

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus

Wiwatpanit

Powers

Dickinson

2012

Journal of Experimental Biology

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“…Other arteries respond to proctolin with slow circumferential, but not longitudinal, contractions. The magnitude of these contractions appears sufficient to account for the measured increases in vascular resistance [220].…”

Section: Effects On Cardiac Musclementioning

confidence: 91%

“…The decapods have received by far the most extensive investigation, and here, proctolin has been shown to modulate exoskeletal muscles/neuromuscular junctions [213][214][215][216], the cardiac neuromuscular system [98, [217][218][219][220][221][222], the stomatogastric neuromuscular system [92, 103, 204, 223-228], the ventilatory system [229], the neural circuitry controlling the swimmerets [230,231], mechanosensory neurons [232][233][234], and hindgut contractility [235]. In non-decapods, proctolin has been shown to be a potent myomodulator [236,237] and to modulate cardiac output [238].…”

Section: Pigment Dispersing Hormonementioning

confidence: 99%

“…Neuropeptides can also cause an increase in resistance in other parts of the circulatory system, such as the anterior arteries. Although the majority of circulatory vessels in the lobsters are not muscular, a recent study [220] showed that Homarus americanus arteries contain actin, myosin, and tropomyosin. The dorsal abdominal artery contains striated muscle cells and responds to electrical stimulation.…”

Section: Effects On Cardiac Musclementioning

confidence: 99%

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Crustacean neuropeptides

Christie

Stemmler

Dickinson

2010

Cell. Mol. Life Sci.

194

407

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Crustaceans have long been used for peptide research. For example, the process of neurosecretion was first formally demonstrated in the crustacean X-organ-sinus gland system, and the first fully characterized invertebrate neuropeptide was from a shrimp. Moreover, the crustacean stomatogastric and cardiac nervous systems have long served as models for understanding the general principles governing neural circuit functioning, including modulation by peptides. Here, we review the basic biology of crustacean neuropeptides, discuss methodologies currently driving their discovery, provide an overview of the known families, and summarize recent data on their control of physiology and behavior.

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“…Redistribution of arterial flow is accomplished by muscular cardioarterial valves located at the entrance to each arterial system (Maynard, 1960) and has been demonstrated in several species [in Bathynomus: by Kihara and Kuwasawa (Kihara and Kuwasawa, 1984); in Cancer magister: by McGaw and colleagues (McGaw et al, 1994); in Panulirus japonicas: by Kuramoto and Ebara (Kuramoto and Ebara, 1984); and in Procambarus clarkii: by Reiber (Reiber, 1994)]. Beyond the cardio-arterial valves, the vasculature has been shown to contain some contractile elements, yet the functional significance of this has yet to be determined (Shadwick et al, 1990;Wilkens, 1997;Wilkens and Taylor, 2003;Wilkens et al, 2008). One exception, the posterior aorta of the abdomen, contains muscle bands in its lateral walls and also has valves along its length, located at each of the branching segmental lateral vessels, that might allow for changes in resistance Wilkens and Taylor, 2003).…”

Section: Introductionmentioning

confidence: 99%

Changes in cardiac performance during hypoxic exposure in the grass shrimpPalaemonetes pugio

Guadagnoli

Tobita

Reiber

2011

Journal of Experimental Biology

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SUMMARYIn hearts of higher invertebrates as well as vertebrates, the work performed by the ventricle is a function of both rate and contractility. Decapod crustaceans experience a hypoxia-induced bradycardia that is thought to result in an overall reduction in cardiac work; however, this hypothesis has not yet been tested and is the primary purpose of this study. In the grass shrimp Palaemonetes pugio, cardiac pressure and area data were obtained simultaneously, and in vivo, under normoxic (20.2kPaO 2 ) and hypoxic (6.8 or 2.2kPaO 2 ) conditions and integrated to generate pressure-area (P-A) loops. The area enclosed by the P-A loop provides a measure of stroke work and, when multiplied by the heart rate, provides an estimate of both cardiac work and myocardial O 2 consumption. Changes in intra-cardiac pressure (dp/dt) are correlated to the isovolemic contraction phase and provide an indication of stroke work. At both levels of hypoxic exposure, intra-cardiac pressure, dp/dt, stroke work and cardiac work fell significantly. The significant decrease in intra-cardiac pressure provides the primary mechanism for the decrease in stroke work, and, when coupled with the hypoxia-induced bradycardia, it contributes to an overall fall in cardiac work. Compared with normoxic P-A loops, hypoxic P-A loops (at both levels of hypoxia) become curvilinear, indicating a fall in peripheral resistance (which might account for the reduction in intra-cardiac pressure), which would reduce both stroke work and cardiac work and ultimately would serve to reduce myocardial O 2 consumption. This is the most direct evidence to date indicating that the hypoxia-induced bradycardia observed in many decapod crustaceans reduces cardiac work and is therefore energetically favorable during acute exposure to conditions of low oxygen.

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Elasticity, unexpected contractility and the identification of actin and myosin in lobster arteries

Abstract: SUMMARY

Cited by 15 publications

References 32 publications

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus

Crustacean neuropeptides

Changes in cardiac performance during hypoxic exposure in the grass shrimpPalaemonetes pugio

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