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Takahashi T, Takigami S, Sunada H, Lukowiak K, Sakakibara M. Critical period of memory enhancement during taste avoidance conditioning in Lymnaea stagnalis. PLoS One 2013; 8:e75276. [PMID: 24098373 PMCID: PMC3789661 DOI: 10.1371/journal.pone.0075276] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/14/2013] [Indexed: 01/06/2023] Open
Abstract
The present study investigated the optimal training procedure leading to long-lasting taste avoidance behavior in Lymnaea. A training procedure comprising 5 repeated pairings of a conditional stimulus (CS, sucrose), with an unconditional stimulus (US, a tactile stimulation to the animal's head), over a 4-day period resulted in an enhanced memory formation than 10 CS-US repeated pairings over a 2-day period or 20 CS-US repeated pairings on a single day. Backward conditioning (US-CS) pairings did not result in conditioning. Thus, this taste avoidance conditioning was CS-US pairing specific. Food avoidance behavior was not observed following training, however, if snails were immediately subjected to a cold-block (4°C for 10 min). It was critical that the cold-block be applied within 10 min to block long-term memory (LTM) formation. Further, exposure to the cold-block 180 min after training also blocked both STM and LTM formation. The effects of the cold-block on subsequent learning and memory formation were also examined. We found no long lasting effects of the cold-block on subsequent memory formation. If protein kinase C was activated before the conditioning paradigm, snails could still acquire STM despite exposure to the cold-block.
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Affiliation(s)
- Tomoyo Takahashi
- School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka, Japan
| | - Satoshi Takigami
- Graduate School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka, Japan
- Graduate School of Bioscience, Tokai University, Numazu, Shizuoka, Japan
| | - Hiroshi Sunada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Canada
| | - Manabu Sakakibara
- School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka, Japan
- Graduate School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka, Japan
- Graduate School of Bioscience, Tokai University, Numazu, Shizuoka, Japan
- * E-mail:
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Ito E, Kojima S, Lukowiak K, Sakakibara M. From likes to dislikes: conditioned taste aversion in the great pond snail (Lymnaea stagnalis). CAN J ZOOL 2013. [DOI: 10.1139/cjz-2012-0292] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neural circuitry comprising the central pattern generator (CPG) that drives feeding behavior in the great pond snail (Lymnaea stagnalis (L., 1758)) has been worked out. Because the feeding behavior undergoes associative learning and long-term memory (LTM) formation, it provides an excellent opportunity to study the causal neuronal mechanisms of these two processes. In this review, we explore some of the possible causal neuronal mechanisms of associative learning of conditioned taste aversion (CTA) and its subsequent consolidation processes into LTM in L. stagnalis. In the CTA training procedure, a sucrose solution, which evokes a feeding response, is used as the conditioned stimulus (CS) and a potassium chloride solution, which causes a withdrawal response, is used as the unconditioned stimulus (US). The pairing of the CS–US alters both the feeding response of the snail and the function of a pair of higher order interneurons in the cerebral ganglia. Following the acquisition of CTA, the polysynaptic inhibitory synaptic input from the higher order interneurons onto the feeding CPG neurons is enhanced, resulting in suppression of the feeding response. These changes in synaptic efficacy are thought to constitute a “memory trace” for CTA in L. stagnalis.
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Affiliation(s)
- E. Ito
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki 769-2193, Japan
| | - S. Kojima
- Sandler Neurosciences Center, University of California, San Francisco, 675 Nelson Rising Lane 518, San Francisco, CA 94143-0444, USA
| | - K. Lukowiak
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - M. Sakakibara
- School of High-Technology for Human Welfare, Tokai University, 317 Nishino, Numazu 410-0321, Japan
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Geiger JE, Magoski NS. Ca2+-induced Ca2+ release in Aplysia bag cell neurons requires interaction between mitochondrial and endoplasmic reticulum stores. J Neurophysiol 2008; 100:24-37. [PMID: 18463180 DOI: 10.1152/jn.90356.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intracellular Ca2+ is influenced by both Ca2+ influx and release. We examined intracellular Ca2+ following action potential firing in the bag cell neurons of Aplysia californica. Following brief synaptic input, these neuroendocrine cells undergo an afterdischarge, resulting in elevated Ca2+ and the secretion of neuropeptides to initiate reproduction. Cultured bag cell neurons were injected with the Ca2+ indicator, fura-PE3, and subjected to simultaneous imaging and electrophysiology. Delivery of a 5-Hz, 1-min train of action potentials (mimicking the fast phase of the afterdischarge) produced a Ca2+ rise that markedly outlasted the initial influx, consistent with Ca2+-induced Ca2+ release (CICR). This response was attenuated by about half with ryanodine or depletion of the endoplasmic reticulum (ER) by cyclopiazonic acid. However, depletion of the mitochondria, with carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone, essentially eliminated CICR. Dual depletion of the ER and mitochondria did not reduce CICR further than depletion of the mitochondria alone. Moreover, tetraphenylphosphonium, a blocker of mitochondrial Ca2+ release, largely prevented CICR. The Ca2+ elevation during and subsequent to a stimulus mimicking the full afterdischarge was prominent and enhanced by protein kinase C activation. Traditionally, the ER is seen as the primary Ca2+ source for CICR. However, bag cell neuron CICR represents a departure from this view in that it relies on store interaction, where Ca2+ released from the mitochondria may in turn liberate Ca2+ from the ER. This unique form of CICR may be used by both bag cell neurons, and other neurons, to initiate secretion, activate channels, or induce gene expression.
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Affiliation(s)
- Julia E Geiger
- Department of Physiology, Queen's University, Kingston, Ontario, Canada
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Woodward OM, Willows AOD. Nervous control of ciliary beating by Cl-, Ca2+ and calmodulin inTritonia diomedea. J Exp Biol 2006; 209:2765-73. [PMID: 16809467 DOI: 10.1242/jeb.02377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYIn vertebrates, motile cilia line airways, oviducts and ventricles. Invertebrate cilia often control feeding, swimming and crawling, or gliding. Yet control and coordination of ciliary beating remains poorly understood. Evidence from the nudibranch mollusc, Tritonia diomedea, suggests that locomotory ciliated epithelial cells may be under direct electrical control. Here we report that depolarization of ciliated pedal epithelial (CPE)cells increases ciliary beating frequency (CBF), and elicits CBF increases similar to those caused by dopamine and the neuropeptide, TPep-NLS. Further,four CBF stimulants (zero external Cl-, depolarization, dopamine and TPep-NLS) depend on a common mode of action, viz. Ca2+influx, possibly through voltage-gated Ca2+ channels, and can be blocked by nifedipine. Ca2+ influx alone, however, does not provide all the internal Ca2+ necessary for CBF change. Ryanodine receptor(RyR) channel-gated internal stores are also necessary for CBF excitation. Caffeine can stimulate CBF and is sensitive to the presence of the RyR blocker dantrolene. Dantrolene also reduces CBF excitation induced by dopamine and TPep-NLS. Finally, W-7 and calmidazolium both block CBF excitation by caffeine and dopamine, and W-7 is effective at blocking TPep-NLS excitation. The effects of calmidazolium and W-7 suggest a role for Ca2+-calmodulin in regulating CBF, either directly or via Ca2+-calmodulin dependent kinases or phosphodiesterases. From these results we hypothesize dopamine and TPep-NLS induce depolarization-driven Ca2+ influx and Ca2+ release from internal stores that activates Ca2+-calmodulin, thereby increasing CBF.
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Affiliation(s)
- Owen M Woodward
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA.
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Sakakibara M. Comparative study of visuo-vestibular conditioning in Lymnaea stagnalis. THE BIOLOGICAL BULLETIN 2006; 210:298-307. [PMID: 16801503 DOI: 10.2307/4134566] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In this review, we compare the current understanding of visuo-vestibular conditioning in Hermissenda crassicornis and Lymnaea stagnalis on the basis of behavioral, electrophysiologic, and morphologic studies. Paired presentation of a photic conditioned stimulus (CS) and an orbital rotation unconditioned stimulus (US) results in conditioned escape behavior in both species. In Hermissenda, changes in excitability of type B photoreceptors and morphologic modifications at the axon terminals follow conditioning. Caudal hair cells, which detect mechanical turbulence, have reciprocal inhibition with type B photoreceptors. In Lymnaea, the interaction between photoreceptors and hair cells is dependent on statocyst location. Furthermore, the organization of the Lymnaea eye is complex, with more than 100 photoreceptors distributed in a uniquely folded retina. Although the optimal conditions to produce long-term memory (memory persistent for >1 week) are almost identical in Hermissenda and Lymnaea, physiologic and morphologic differences suggest that the neuronal mechanisms underlying learning and memory are distinct.
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Affiliation(s)
- Manabu Sakakibara
- Laboratory of Neurobiological Engineering, Department of Biological Science and Technology, School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu 410-0321, Shizuoka, Japan.
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Sakakibara M, Aritaka T, Iizuka A, Suzuki H, Horikoshi T, Lukowiak K. Electrophysiological Responses to Light of Neurons in the Eye and Statocyst of Lymnaea stagnalis. J Neurophysiol 2005; 93:493-507. [PMID: 15306628 DOI: 10.1152/jn.00692.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lymnaea can be classically conditioned by pairing photic stimulation with a rotational stimulus. The electrophysiological properties of the Lymnaea photoreceptors and statocyst neurons are incompletely known. There are 2 types of ocular photoreceptors and 3 types of statocyst “hair cells.” Type A photoreceptors had a response latency from 200 to 400 ms, with a graded depolarizing response having maximum action spectra at 480–500 nm, corresponding to the βmax of rhodopsin. Additionally they extend their axons in the direction of the other type of photoreceptor neuron, the type T cell. These neurons have a 2-component response to light: a response reversibly reduced in Ca2+-free saline, and a component persisting in Ca2+-free saline. Type T cells send processes into the cerebral ganglion and terminate close to the ending of the statocyst hair cells. Hair cells send their terminal branches to the cerebral ganglia close to the terminations of the type T cells. Caudal hair cells respond to a light flash with a depolarization, whereas the rostral cells respond with a hyperpolarization. The response latency in all hair cells was dependent on the stimulus intensity; the brightest light tested had a latency of 200 ms. The photo-induced response was abolished in Ca2+-free saline, whereas it was still present in high Ca2+–high Mg2+ saline, consistent with the hypothesis that the connection between the photoreceptors and hair cells is monosynaptic. Thus the sensory information necessary for forming an association between photic and rotational stimuli converges on the statocyst neurons.
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Affiliation(s)
- Manabu Sakakibara
- Laboratory of Neurobiological Engineering, Department of Biological Science and Technology, School of High-Technology for Human Welfare, Tokai University, 317 Nishino, Numazu 410-0321, Shizuoka, Japan.
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