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Rivi V, Rigillo G, Batabyal A, Lukowiak K, Pani L, Tascedda F, Benatti C, Blom JMC. Different stressors uniquely affect the expression of endocannabinoid-metabolizing enzymes in the central ring ganglia of Lymnaea stagnalis. J Neurochem 2024. [PMID: 38922726 DOI: 10.1111/jnc.16147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 04/16/2024] [Accepted: 05/16/2024] [Indexed: 06/28/2024]
Abstract
The endocannabinoid system (ECS) plays an important role in neuroprotection, neuroplasticity, energy balance, modulation of stress, and inflammatory responses, acting as a critical link between the brain and the body's peripheral regions, while also offering promising potential for novel therapeutic strategies. Unfortunately, in humans, pharmacological inhibitors of different ECS enzymes have led to mixed results in both preclinical and clinical studies. As the ECS has been highly conserved throughout the eukaryotic lineage, the use of invertebrate model organisms like the pond snail Lymnaea stagnalis may provide a flexible tool to unravel unexplored functions of the ECS at the cellular, synaptic, and behavioral levels. In this study, starting from the available genome and transcriptome of L. stagnalis, we first identified putative transcripts of all ECS enzymes containing an open reading frame. Each predicted protein possessed a high degree of sequence conservation to known orthologues of other invertebrate and vertebrate organisms. Sequences were confirmed by qualitative PCR and sequencing. Then, we investigated the transcriptional effects induced by different stress conditions (i.e., bacterial LPS injection, predator scent, food deprivation, and acute heat shock) on the expression levels of the enzymes of the ECS in Lymnaea's central ring ganglia. Our results suggest that in Lymnaea as in rodents, the ECS is involved in mediating inflammatory and anxiety-like responses, promoting energy balance, and responding to acute stressors. To our knowledge, this study offers the most comprehensive analysis so far of the ECS in an invertebrate model organism.
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Affiliation(s)
- Veronica Rivi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Giovanna Rigillo
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Anuradha Batabyal
- Department of Physical and Natural Sciences, FLAME University, Pune, India
| | - Ken Lukowiak
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Luca Pani
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, Florida, USA
| | - Fabio Tascedda
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- CIB, Consorzio Interuniversitario Biotecnologie, Trieste, Italy
| | - Cristina Benatti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - Johanna M C Blom
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
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2
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Swinton E, Swinton C, Lukowiak K. Shell damage leads to enhanced memory formation in Lymnaea. ACTA ACUST UNITED AC 2019; 222:jeb.207571. [PMID: 31431472 DOI: 10.1242/jeb.207571] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/11/2019] [Indexed: 12/14/2022]
Abstract
Ecologically relevant stressors alter the ability of the pond snail, Lymnaea stagnalis, to form long-term memory (LTM). Here, we show that an environmentally relevant stressor, shell damage, has a dramatic effect on the enhancement of LTM formation. Damage in the form of a shell clip 24 h before operant conditioning training resulted in long-term memory (LTM) formation following a single 0.5 h training session (TS). Typically, in these snails, two 0.5 h TSs with a 1 h interval between the sessions are required to cause LTM formation. We show here that even with a 72 h interval between shell clip and training, memory enhancement still occurred. The stress associated with shell clip could be mitigated by an ongoing high-Ca2 + pond water environment, an injection of propranolol and a DNA methylation blocker. However, use of an anaesthetic (MgCl2) during the clip or intermittent exposure to the high-Ca2 + pond water environment did not mitigate the stress associated with the shell clip. Shell clip was also sufficient to cause juvenile snails, which neither learn nor form memory, to gain the capacity to form LTM. Together, the experiments demonstrate that shell clipping is an environmentally relevant stressor that can cause enhancement of LTM formation.
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Affiliation(s)
- Erin Swinton
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada, T2N 4N1
| | - Cayley Swinton
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada, T2N 4N1
| | - Ken Lukowiak
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada, T2N 4N1
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3
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Rothwell CM, Lukowiak K. Strain transformation: Enhancement of invertebrate memory in a new rearing environment. J Exp Biol 2019; 222:jeb.205112. [DOI: 10.1242/jeb.205112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/24/2019] [Indexed: 11/20/2022]
Abstract
Memory formation is influenced by a variety of factors, including the environmental conditions in which an organism is reared. Here, we studied the memory-forming ability of the lab-bred B-strain of Lymnaea following a change in their rearing environment from Brock University to the University of Calgary. We have previously demonstrated that this move enhances memory-forming ability and here we studied the magnitude of this phenotypic change. Once reared to adulthood at the University of Calgary, the B-strain animals were first tested to determine how many training sessions were required for the formation of long-term memory (LTM) to occur. Following this change in environment, the B-strain transformed into a ‘smart’ lab-bred strain requiring only a single 0.5 h session to form LTM. Next, we tested whether exposure to physiologically relevant stressors would block the formation of LTM in this ‘transformed’ B-strain, as this obstruction has previously been observed in ‘smart’ snails collected from the wild. Interestingly, neither stressor tested in this study perturbed memory formation in this ‘transformed’ lab-bred strain. Additionally, both the ‘smart’ memory phenotype, as well as the increased stress resiliency, were observed in the second generation of ‘transformed’ B-strain at both the juvenile and adult stages. This suggests that a change in rearing environment can contribute to the memory-forming ability of lab-bred Lymnaea.
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Affiliation(s)
- Cailin M. Rothwell
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada
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Mitchell MD, Bairos-Novak KR, Ferrari MCO. Mechanisms underlying the control of responses to predator odours in aquatic prey. J Exp Biol 2017; 220:1937-1946. [DOI: 10.1242/jeb.135137] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
ABSTRACT
In aquatic systems, chemical cues are a major source of information through which animals are able to assess the current state of their environment to gain information about local predation risk. Prey use chemicals released by predators (including cues from a predator's diet) and other prey (such as alarm cues and disturbance cues) to mediate a range of behavioural, morphological and life-history antipredator defences. Despite the wealth of knowledge on the ecology of antipredator defences, we know surprisingly little about the physiological mechanisms that control the expression of these defensive traits. Here, we summarise the current literature on the mechanisms known to specifically mediate responses to predator odours, including dietary cues. Interestingly, these studies suggest that independent pathways may control predator-specific responses, highlighting the need for greater focus on predator-derived cues when looking at the mechanistic control of responses. Thus, we urge researchers to tease apart the effects of predator-specific cues (i.e. chemicals representing a predator's identity) from those of diet-mediated cues (i.e. chemicals released from a predator's diet), which are known to mediate different ecological endpoints. Finally, we suggest some key areas of research that would greatly benefit from a more mechanistic approach.
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Affiliation(s)
- Matthew D. Mitchell
- Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
| | | | - Maud C. O. Ferrari
- Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
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5
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Hughes E, Shymansky T, Swinton E, Lukowiak KS, Swinton C, Sunada H, Protheroe A, Phillips I, Lukowiak K. Strain-specific differences of the effects of stress on memory in Lymnaea. J Exp Biol 2017; 220:891-899. [DOI: 10.1242/jeb.149161] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/14/2016] [Indexed: 12/17/2022]
Abstract
ABSTRACT
Stress alters the ability to form, recall and maintain memory according to the Yerkes–Dodson/Hebb (YDH) law. The effects of environmentally relevant stressors, such as low environmental calcium and crowding, on learning and memory have previously been described in a laboratory-reared ‘average’ strain of Lymnaea stagnalis (i.e. the Dutch strain) as well as two strains of freshly collected L. stagnalis with enhanced memory formation abilities (i.e. ‘smart’ snails). Here, we use L. stagnalis to study the effects of other environmentally relevant stressors on memory formation in two other strains of freshly collected snails, one ‘smart’ and one ‘average’. The stressors we examined are thermal, resource restriction combined with food odour, predator detection and, for the first time, tissue injury (shell damage). We show that the same stressor has significantly different effects on memory formation depending on whether snails are ‘smart’ or ‘average’. Specifically, our data suggest that a stressor or a combination of stressors act to enhance memory in ‘average’ snails but obstruct memory formation in ‘smart’ snails. These results are consistent with the YDH law and our hypothesis that ‘smart’ snails are more easily stressed than ‘average’ snails.
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Affiliation(s)
- Emily Hughes
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Tamila Shymansky
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Erin Swinton
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Kai S. Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Cayley Swinton
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Hiroshi Sunada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Amy Protheroe
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Iain Phillips
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
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6
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Carpenter S, Rothwell CM, Wright ML, de Hoog E, Walker S, Hudson E, Spencer GE. Extending the duration of long-term memories: Interactions between environmental darkness and retinoid signaling. Neurobiol Learn Mem 2016; 136:34-46. [PMID: 27646787 DOI: 10.1016/j.nlm.2016.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 08/30/2016] [Accepted: 09/15/2016] [Indexed: 01/05/2023]
Abstract
Retinoid signaling plays an important role in hippocampal-dependent vertebrate memories. However, we have previously demonstrated that retinoids are also involved in the formation of long-term implicit memory following operant conditioning of the invertebrate mollusc Lymnaea stagnalis. Furthermore, we have discovered an interaction between environmental light/dark conditions and retinoid signaling and the ability of both to convert intermediate-term memory into long-term memory. In this study, we extend these findings to show that retinoid receptor agonists and environmental darkness can both also extend the duration of long-term memory. Interestingly, exposure to constant environmental darkness significantly increased the expression of retinoid receptors in the adult central nervous system, as well as induced specific changes in a key neuron mediating the conditioned behaviour. These studies not only shed more light on how retinoids influence memory formation, but also further link environmental light conditions to the retinoid signaling pathway.
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Affiliation(s)
- Sevanne Carpenter
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Cailin M Rothwell
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Michelle L Wright
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Eric de Hoog
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Sarah Walker
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Emma Hudson
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Gaynor E Spencer
- Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
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Forest J, Sunada H, Dodd S, Lukowiak K. Training Lymnaea in the presence of a predator scent results in a long-lasting ability to form enhanced long-term memory. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:399-409. [PMID: 27138222 DOI: 10.1007/s00359-016-1086-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 12/25/2022]
Abstract
Lymnaea exposed to crayfish effluent (CE) gain an enhanced ability to form long-term memory (LTM). We test the hypothesis that a single CE exposure and operant conditioning training leads to long lasting changes in the capability of snails to form LTM when tested in pond water four weeks later. We trained both juvenile and adult snails with a single 0.5 h training session in CE and show that LTM was present 24 h later. Snails trained in a similar manner in just pond water show no LTM. We then asked if such training in CE conferred enhanced memory forming capabilities on these snails four weeks later. That is, would LTM be formed in these snails four weeks later following a single 0.5 h training session in pond water? We found that both adult and juvenile snails previously trained in CE one month previously had enhanced LTM formation abilities. The injection of a DNA methylation blocker, 5-AZA, prior to training in adult snails blocked enhanced LTM formation four weeks later. Finally, this enhanced LTM forming ability was not passed on to the next generation of snails.
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Affiliation(s)
- Jeremy Forest
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.,University Claude Bernard, Lyon, France
| | - Hiroshi Sunada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Shawn Dodd
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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8
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Shymansky T, Protheroe A, Hughes E, Swinton C, Swinton E, Lukowiak KS, Phillips I, Lukowiak K. Juveniles of Lymnaea smart snails do not perseverate and have the capacity to form LTM. J Exp Biol 2016; 220:408-413. [DOI: 10.1242/jeb.147884] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/11/2016] [Indexed: 01/18/2023]
Abstract
Previously, it was concluded that the nervous systems of the juvenile snails were not capable of mediating LTM. However, exposure and training of those juvenile snails in the presence of a predator cue significantly altered their ability to learn and form LTM. In addition, there are some strains of Lymnaea which have been identified as ‘smart’. These snails form LTM significantly better than the lab-bred strain. Here we show that juveniles of two smart snail strains are not only capable of associative learning, but also have the capacity to form LTM following a single 0.5h training session. We also show that freshly collected ‘wild’ ‘average’ juveniles are also not able to form LTM. Thus, the smart snail phenotype in these strains is expressed in juveniles.
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Affiliation(s)
- Tamila Shymansky
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Amy Protheroe
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Emily Hughes
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Cayley Swinton
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Erin Swinton
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Kai S. Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Iain Phillips
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary AB T2N 4N1, Canada
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9
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Adamo SA, Kovalko I, Mosher B. The behavioural effects of predator-induced stress responses in the cricket (Gryllus texensis): the upside of the stress response. ACTA ACUST UNITED AC 2014; 216:4608-14. [PMID: 24307711 DOI: 10.1242/jeb.094482] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Predator-induced stress responses are thought to reduce an animal's risk of being eaten. Therefore, these stress responses should enhance anti-predator behaviour. We found that individual insects (the cricket Gryllus texensis) show reliable behavioural responses (i.e. behavioural types) in a plus-shaped maze. An individual's behaviour in the plus maze remained consistent for at least 1/2 of its adult life. However, after exposure to a model predator, both male and female crickets showed a reduced period of immobility and an increased amount of time spent under shelter compared with controls. These changes could be mimicked by injections of the insect stress neurohormone octopamine. These behavioural changes probably aid crickets in evading predators. Exposure to a model predator increased the ability of crickets to escape a live predator (a bearded dragon, Pogona vitticeps). An injection of octopamine had the same effect, showing that stress hormones can reduce predation. Using crickets to study the fitness consequences of predator-induced stress responses will help integrate ecological and biomedical concepts of 'stress'.
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Affiliation(s)
- Shelley A Adamo
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
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10
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Takigami S, Sunada H, Lukowiak K, Sakakibara M. Spaced taste avoidance conditioning in Lymnaea. Neurobiol Learn Mem 2014; 107:79-86. [DOI: 10.1016/j.nlm.2013.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 10/31/2013] [Accepted: 10/31/2013] [Indexed: 12/11/2022]
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11
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Spencer G, Rothwell C. Behavioural and network plasticity following conditioning of the aerial respiratory response of a pulmonate mollusc. CAN J ZOOL 2013. [DOI: 10.1139/cjz-2012-0291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Most molluscs perform respiration using gills, but the pulmonate molluscs have developed a primitive lung with which they perform pulmonary respiration. The flow of air into this lung occurs through an opening called the pneumostome, and pulmonate molluscs travel to the surface of the water to obtain oxygen from the surrounding atmosphere. The aerial respiratory behaviour of the pulmonate mollusc, the great pond snail (Lymnaea stagnalis (L., 1758)), has been well studied, and a three-neuron central pattern generator (CPG) controlling this rhythmic behaviour has been identified. The aerial respiratory behaviour of L. stagnalis can be operantly conditioned and plasticity within the CPG has been associated with the conditioned response. In this review, we describe both the aerial respiratory behaviour and the underlying neuronal network of this pulmonate mollusc, and then discuss both the behavioural and network plasticity that results from the conditioning of this behaviour.
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Affiliation(s)
- G.E. Spencer
- Department of Biological Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON L2S 3A1, Canada
| | - C.M. Rothwell
- Department of Biological Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON L2S 3A1, Canada
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12
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Affiliation(s)
- Michael Clinchy
- Department of Biology; University of Victoria; Victoria; British Columbia; V8W 3N5; Canada
| | - Michael J. Sheriff
- Institute of Arctic Biology; University of Alaska Fairbanks; Fairbanks; Alaska; 99775; USA
| | - Liana Y. Zanette
- Department of Biology; University of Western Ontario; London; Ontario; N6A 5B7; Canada
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13
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Dalesman S, Rundle SD, Lukowiak K. Microgeographical variability in long-term memory formation in the pond snail, Lymnaea stagnalis. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Sunada H, Horikoshi T, Lukowiak K, Sakakibara M. Increase in excitability of RPeD11 results in memory enhancement of juvenile and adult Lymnaea stagnalis by predator-induced stress. Neurobiol Learn Mem 2010; 94:269-77. [PMID: 20601028 DOI: 10.1016/j.nlm.2010.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 06/05/2010] [Accepted: 06/17/2010] [Indexed: 12/13/2022]
Abstract
Memory consolidation following learning is a dynamic process. Thus, long-term memory (LTM) formation can be modulated by many factors, including stress. We examined how predator-induced stress enhances LTM formation in the pond snail Lymnaea stagnalis at both the behavioral and electrophysiological levels. Training snails in crayfish effluent (CE; i.e., water from an aquarium containing crayfish) significantly enhanced LTM. That is, while memory persists for only 3h in adult control experiments following a single 0.5-h training session in pond water in which the pneumostome receives a contingent tactile stimulus to the pneumostome; when the snails are trained in CE, the memory persists for at least 24h. In juveniles, the data are more dramatic. Juveniles are unable to form LTM in pond water, but form LTM when trained in CE. Here we examined whether juvenile snails form LTM following a one-trial training procedure (1TT). Following the 1TT procedure (a single-trial aversive operant conditioning training procedure), juveniles do not form LTM, unless trained in CE. Concomitantly, we observe changes in the excitability of RPeD11, a key neuron mediating the whole snail withdrawal response, which may be a neural correlate of enhanced memory formation.
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Affiliation(s)
- Hiroshi Sunada
- Graduate School of Bioscience, Tokai University, Numazu 410-0321, Japan
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