The effects of prospective anaesthetic substances on cephalopods: Summary of original data and a brief review of studies over the last two decades

Gleadall, Ian G.

doi:10.1016/j.jembe.2013.02.008

Cited by 49 publications

(64 citation statements)

References 51 publications

(48 reference statements)

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“…This is also consistent with a previous study showing that discrete and complex components of arm movements have no central topographical organization in the higher motor center, but are rather distributed over wide regions in the octopus (Zullo et al, 2009). Furthermore, tracer injection of chromatophores on the skin and electrical stimulation at the posterior chromatophore lobe in squids has also demonstrated that there is no relationship between the loci in the lower motor center and regions of chromatophore expansion at the periphery (Dubas et al, 1986a;Dubas et al, 1986b). Our findings support the hypothesis that motor control in cephalopods is nonsomato- topically or diffusedly organized in the brain.…”

Section: Control Of Body Coloration Is Ipsilaterally Dominant and Orgsupporting

confidence: 78%

Mosaic Organization of Body Pattern Control in the Optic Lobe of Squids

Liu

Chiao

2017

J. Neurosci.

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Cephalopods in nature undergo highly dynamic skin coloration changes that allow rapid camouflage and intraspecies communication. The optic lobe is thought to play a key role in controlling the expansion of the chromatophores that generate these diverse body patterns. However, the functional organization of the optic lobe and neural control of the various body patterns by the optic lobe are largely unknown. We applied electrical stimulation within the optic lobe to investigate the neural basis of body patterning in the oval squid, Sepioteuthis lessoniana. Most areas in the optic lobe mediated predominately ipsilateral expansion of chromatophores present on the mantle, but not on the head and arms; furthermore, the expanded areas after electrical stimulation were positively correlated with an increase in stimulating voltage and stimulation depth. These results suggest a unilaterally dominant and vertically converged organization of the optic lobe. Furthermore, analyzing 14 of the elicited body pattern components and their corresponding stimulation sites revealed that the same components can be elicited by stimulating different parts of the optic lobe and that various subsets of these components can be coactivated by stimulating the same area. These findings suggest that many body pattern components may have multiple motor units in the optic lobe and that these are organized in a mosaic manner. The multiplicity associated with the nature of the neural controls of these components in the cephalopod brain thus reflects the versatility of the individual components during the generation of diverse body patterns.

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Section: Control Of Body Coloration Is Ipsilaterally Dominant and Orgsupporting

confidence: 78%

Mosaic Organization of Body Pattern Control in the Optic Lobe of Squids

Liu

Chiao

2017

J. Neurosci.

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“…Physiological and cellular effects of the agents used for inducing anesthesia are relatively well-understood (Fish et al, 2008; Chau, 2010; see also Sneddon, 2012). In contrast for cephalopods, whilst the potential anesthetic properties of about 20 agents have been explored (for review see for example: Gleadall, 2013; Fiorito et al, 2015), few studies regarding the physiological effects on the animals, including the cardiac ones, are available (review in: Andrews et al, 2013). …”

Section: Introductionmentioning

confidence: 99%

“…However it is only after Messenger et al that the use of MgCl2 increased. Until then urethane (i.e., ethyl carbamate) was the most widely used anesthetic agent for surgery (e.g., brain lesions) in octopus and other cephalopods (e.g.,: Sanders and Young, 1940; Boycott and Young, 1950, 1955; Young, 1971a; for review see also Gleadall, 2013). Ethyl carbamate was abandoned because of its elevated carcinogenicity (Nomura, 1975).…”

Section: Introductionmentioning

confidence: 99%

“…Magnesium chloride, either in sea water or as a mixture of sea water and distilled water, fulfills the criteria commonly used for assessing general anesthesia in cephalopods (Andrews and Tansey, 1981; for review and discussion see: Andrews et al, 2013; Gleadall, 2013; Fiorito et al, 2015), in particular: skin pallor (mantle and arms) and loss of texture, loss of arm muscle tone and sucker adhesiveness, loss of the righting reflex, absence of a response to a noxious mechanical stimulus applied to the arms or mantle and marked suppression of ventilation.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Different Formulations of Magnesium Chloride Used As Anesthetic Agents on the Performance of the Isolated Heart of Octopus vulgaris

et al. 2016

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Magnesium chloride (MgCl2) is commonly used as a general anesthetic in cephalopods, but its physiological effects including those at cardiac level are not well-characterized. We used an in vitro isolated perfused systemic heart preparation from the common octopus, Octopus vulgaris, to investigate: (a) if in vivo exposure to MgCl2 formulations had an effect on cardiac function in vitro and, if so, could this impact recovery and (b) direct effects of MgCl2 formulations on cardiac function. In vitro hearts removed from animals exposed in vivo to 3.5% MgCl2 in sea water (20 min) or to a mixture of MgCl2+ ethanol (1.12/1%; 20 min) showed cardiac function (heart rate, stroke volume, cardiac output) comparable to hearts removed from animals killed under hypothermia. However, 3.5% MgCl2 (1:1, sea water: distilled water, 20 min) produced a significant impairment of the Frank-Starling response as did 45 min exposure to the MgCl2+ ethanol mixture. Perfusion of the isolated heart with MgCl2± ethanol formulations produced a concentration-related bradycardia (and arrest), a decreased stroke volume and cardiac output indicating a direct effect on the heart. The cardiac effects of MgCl2 are discussed in relation to the involvement of magnesium, sodium, chloride, and calcium ions, exposure time and osmolality of the formulations and the implications for the use of various formulations of MgCl2 as anesthetics in octopus. Overall, provided that the in vivo exposure to 3.5% MgCl2 in sea water or to a mixture of MgCl2+ ethanol is limited to ~20 min, residual effects on cardiac function are unlikely to impact post-anesthetic recovery.

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“…Previous attempts to anesthetize cephalopods have used a variety of substances (see Gleadall, 2013) including muscle relaxants such as magnesium chloride (Messenger et al, 1985; Mooney et al, 2010; Gonçalves et al, 2012; Gleadall, 2013; Butler-Struben et al, 2018) and low temperatures (Andrews and Tansey, 1981), resulting in paralysis of the animals rather than anesthesia. Even ethanol has been used for short duration tagging of the oval squid (Ikeda et al, 2009).…”

Section: Actions Of Anesthetics On Cephalopod Molluscsmentioning

confidence: 99%

Sense and Insensibility – An Appraisal of the Effects of Clinical Anesthetics on Gastropod and Cephalopod Molluscs as a Step to Improved Welfare of Cephalopods

et al. 2018

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Recent progress in animal welfare legislation stresses the need to treat cephalopod molluscs, such as Octopus vulgaris, humanely, to have regard for their wellbeing and to reduce their pain and suffering resulting from experimental procedures. Thus, appropriate measures for their sedation and analgesia are being introduced. Clinical anesthetics are renowned for their ability to produce unconsciousness in vertebrate species, but their exact mechanisms of action still elude investigators. In vertebrates it can prove difficult to specify the differences of response of particular neuron types given the multiplicity of neurons in the CNS. However, gastropod molluscs such as Aplysia, Lymnaea, or Helix, with their large uniquely identifiable nerve cells, make studies on the cellular, subcellular, network and behavioral actions of anesthetics much more feasible, particularly as identified cells may also be studied in culture, isolated from the rest of the nervous system. To date, the sorts of study outlined above have never been performed on cephalopods in the same way as on gastropods. However, criteria previously applied to gastropods and vertebrates have proved successful in developing a method for humanely anesthetizing Octopus with clinical doses of isoflurane, i.e., changes in respiratory rate, color pattern and withdrawal responses. However, in the long term, further refinements will be needed, including recordings from the CNS of intact animals in the presence of a variety of different anesthetic agents and their adjuvants. Clues as to their likely responsiveness to other appropriate anesthetic agents and muscle relaxants can be gained from background studies on gastropods such as Lymnaea, given their evolutionary history.

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The effects of prospective anaesthetic substances on cephalopods: Summary of original data and a brief review of studies over the last two decades

Cited by 49 publications

References 51 publications

Mosaic Organization of Body Pattern Control in the Optic Lobe of Squids

Mosaic Organization of Body Pattern Control in the Optic Lobe of Squids

Effect of Different Formulations of Magnesium Chloride Used As Anesthetic Agents on the Performance of the Isolated Heart of Octopus vulgaris

Sense and Insensibility – An Appraisal of the Effects of Clinical Anesthetics on Gastropod and Cephalopod Molluscs as a Step to Improved Welfare of Cephalopods

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