Seasonal determinants of the life cycle in two species of Aplysia found in shallow waters along the Mediterranean coast of Israel

Gev, S.; Achituv, Y.; Susswein, Abraham J.

doi:10.1016/0022-0981(84)90038-8

Cited by 25 publications

(9 citation statements)

References 9 publications

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“…Training and testing during the respective active or inactive phases were opposite in the 2 Aplysia species. A. fasciata are found locally only during the summer months (Gev et al, 1984). When A. fasciata were unavailable, which was most of the year, A. californica were used.…”

Section: Materials and Methodsmentioning

confidence: 99%

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

Levy

Levitan

Susswein

2016

eLife

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Brief experiences while a memory is consolidated may capture the consolidation, perhaps producing a maladaptive memory, or may interrupt the consolidation. Since consolidation occurs during sleep, even fleeting experiences when animals are awakened may produce maladaptive long-term memory, or may interrupt consolidation. In a learning paradigm affecting Aplysia feeding, when animals were trained after being awakened from sleep, interactions between new experiences and consolidation were prevented by blocking long-term memory arising from the new experiences. Inhibiting protein synthesis eliminated the block and allowed even a brief, generally ineffective training to produce long-term memory. Memory formation depended on consolidative proteins already expressed before training. After effective training, long term memory required subsequent transcription and translation. Memory formation during the sleep phase was correlated with increased CREB1 transcription, but not CREB2 transcription. Increased C/EBP transcription was a correlate of both effective and ineffective training and of treatments not producing memory.

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Section: Materials and Methodsmentioning

confidence: 99%

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

Levy

Levitan

Susswein

2016

eLife

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“…The species used in each experiment is in each case indicated below. Both A. fasciutu and A. oculifeu are seasonally available along the Israeli coasts (Gev et al, 1984), precluding use of either species yearround. In every case, the species used for a particular experiment is noted.…”

Section: Methodsmentioning

confidence: 99%

Learned changes of feeding behavior in Aplysia in response to edible and inedible foods

Susswein¹,

Schwarz²,

Feldman³

1986

J. Neurosci.

114

184

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Feeding behavior in Aplysia fasciata and A. oculifera is modified by pairing the behavior with reinforcing consequences. Successful and unsuccessful attempts to transfer food from the buccal cavity to the crop act as positive and negative reinforcers, respectively. A number of changes in feeding behavior occur as a result of pairing of feeding with the negative reinforcer: feeding responses become less effective in leading to the entry of food into the buccal cavity; when food does enter the buccal cavity, it exits sooner; swallowing responses after food entry are less likely to occur; Aplysia eventually cease responding to food. Pairing successful transfer of food into the crop with feeding behavior produces opposite effects. Behavioral change is specific to pairing, as shown by lack of change when reinforcement is explicitly unpaired with feeding behavior. Behavioral change is specific to foods with a particular taste and texture; generalization to alternate foods was not observed. In spite of cessation of feeding, animals remain aroused, as shown by low response latency to alternate foods. Memory of response change persists for at least 48 hr.

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“…californica will encounter water temperatures ranging from well below 15°C to as high as 25°C (Kupfermann and Carew 1974). [Other Aplysia species, such as A. fasciata in the Mediterranean Sea or A. dactylomela in the Caribbean, live and feed at up to at least 29°C (Carefoot 1987;Gev et al 1984), but the modulatory tuning of the feeding musculature has not been studied in these species.] Aplysia are, of course, poikilotherms that cannot maintain an internal temperature that is appreciably different from that of the surrounding water.…”

Section: Introductionmentioning

confidence: 99%

Temperature Compensation of Neuromuscular Modulation inAplysia

Zhurov¹,

Březina²

2005

Journal of Neurophysiology

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. Physiological systems that must operate over a range of temperatures often incorporate temperature-compensatory mechanisms to maintain their output within a relatively narrow, functional range of values. We analyze here an example in the accessory radula closer (ARC) neuromuscular system, a representative part of the feeding neuromusculature of the sea slug Aplysia. The ARC muscle's two motor neurons, B15 and B16, release, in addition to ACh that contracts the muscle, modulatory peptide cotransmitters that, through a complex network of effects in the muscle, shape the ACh-induced contractions. It is believed that this modulation is critical in optimizing the performance of the muscle for successful, efficient feeding behavior. However, previous work has shown that the release of the modulatory peptides from the motor neurons decreases dramatically with increasing temperature. From 15 to 25°C, for example, release decreases 20-fold. Yet Aplysia live and feed successfully not only at 15°C, but at 25°C and probably at higher temperatures. Here, working with reduced B15/B16 -ARC preparations in vitro as well as a mathematical model of the system, we have found a resolution of this apparent paradox. Although modulator release decreases 20-fold when the temperature is raised from 15 to 25°C, the observed modulation of contraction shape does not decrease at all. Two mechanisms are responsible. First, further downstream within the modulatory network, the modulatory effects themselves-experimentally dissected by exogenous modulator application-have temperature dependencies opposite to that of modulator release, increasing with temperature. Second, the saturating curvature of the dose-response relations within the network diminishes the downstream impact of the decrease of modulator release. Thus two quite distinct mechanisms, one depending on the characteristics of the individual components of the network and the other emerging from the network's structure, combine to compensate for temperature changes to maintain the output of this physiological system. I N T R O D U C T I O NThe rates of individual biochemical reactions and elementary physiological processes vary intrinsically with temperature. Yet the larger physiological systems that are built from these processes must often maintain their output within a relatively narrow, functional range of values. Animals that are active over a range of environmental temperatures must therefore compensate, if they do not regulate their internal temperature, by building temperature-compensatory mechanisms into the structure of their physiological systems. We analyze here an example in the accessory radula closer (ARC) neuromuscular system of the sea slug Aplysia. This system is tuned by a complex network of neuromodulatory effects that, individually, vary greatly with temperature; yet the overall output of the system does not.The ARC muscle is one of the muscles of the buccal mass, a complex structure that produces rhythmic, cyclical movements of the animal's food-grasping organ...

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Seasonal determinants of the life cycle in two species of Aplysia found in shallow waters along the Mediterranean coast of Israel

Cited by 25 publications

References 9 publications

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

Learned changes of feeding behavior in Aplysia in response to edible and inedible foods

Temperature Compensation of Neuromuscular Modulation inAplysia

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