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Loy I, Fernández-Victorero S, Muñiz-Moreno J. Renewal of conditioned tentacle lowering by circadian contextual cues in snails Cornu aspersum. Behav Processes 2020; 178:104144. [PMID: 32445853 DOI: 10.1016/j.beproc.2020.104144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/03/2020] [Accepted: 05/17/2020] [Indexed: 11/18/2022]
Abstract
Previous experiments using tentacle lowering conditioning in terrestrial snails Cornu aspersum have shown extinction and recovery of the conditioned response (CR) as a consequence of both inserting a delay between the extinction and test (spontaneous recovery) and of re-exposing the animal to the unconditioned stimulus after extinction (reinstatement). Two experiments that examined recovery of the CR due to a change in context (renewal effect) were carried out to continue this line of research. In Experiment 1, subjects received conditioning with an odour (CS) followed by extinction in the presence of another odour (CS + C), before being exposed to the original one (CS). In Experiment 2, conditioning and extinction of an odour CS took place in the presence of different circadian contextual cues (hour of the day and presence of light). The results showed that a return to the original context of conditioned training, after the extinction in a different context, either defined by an odour (Experiment 1) or by circadian cues (Experiment 2), produce a recovery of the CR compared to suitable control groups. These results can be interpreted as an instance of ABA renewal effect and they provide information about psychological mechanisms involved in extinction processes.
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Affiliation(s)
- Ignacio Loy
- Department of Psychology, University of Oviedo, Plaza the Feijoo s/n, 33003 Oviedo, Spain.
| | | | - Judit Muñiz-Moreno
- Department of Psychology, University of Oviedo, Plaza the Feijoo s/n, 33003 Oviedo, Spain
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2
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Nikitin V, Solntseva S, Kozyrev S, Nikitin P. Long-term memory consolidation or reconsolidation impairment induces amnesia with key characteristics that are similar to key learning characteristics. Neurosci Biobehav Rev 2020; 108:542-558. [DOI: 10.1016/j.neubiorev.2019.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 09/16/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023]
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3
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Vorster AP, Born J. Wakefulness rather than sleep benefits extinction of an inhibitory operant conditioning memory in Aplysia. Neurobiol Learn Mem 2018; 155:306-312. [DOI: 10.1016/j.nlm.2018.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 04/20/2018] [Accepted: 07/27/2018] [Indexed: 01/16/2023]
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Merlo EM, Milligan KA, Sheets NB, Neufeld CJ, Eastham TM, Estores-Pacheco AK, Steinke D, Hebert PD, Valdés Á, Wyeth RC. Range extension for the region of sympatry between the nudibranchs Hermissenda opalescens and Hermissenda crassicornis in the northeastern Pacific. Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mollusc nudibranch genus Hermissenda Bergh, 1879 was recently discovered to include three pseudocryptic species, dividing a single species H. crassicornis (sensu lato) into H. crassicornis Escholtz, 1831, H. opalescens J.G. Cooper, 1863, and H. emurai Baba, 1937. The species were distinguished by both genetic and morphological evidence, and the distribution of sampled animals suggested the three species had mostly distinct geographical ranges. Here, we report the presence of both H. crassicornis and H. opalescens in Barkley and Clayoquot Sounds, British Columbia, Canada, based on diagnostic characters and molecular data congruent with the differences described for these two species. This result extends the region of sympatry for the two species from northern California, USA, to, at least, Vancouver Island, British Columbia in 2016. Depending on how long this overlap has occurred, the possible northward expansion of H. opalescens would have implications for understanding the effects of short- or long-term environmental changes in ocean temperatures as well as complicating the interpretation of past neurobiological studies of H. crassicornis (sensu lato).
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Affiliation(s)
- Emily M. Merlo
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
| | - Kathryn A. Milligan
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
| | - Nola B. Sheets
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
| | - Christopher J. Neufeld
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
- Quest University Canada, 3200 University Boulevard, Squamish, BC V8B 0N8, Canada
| | - Tao M. Eastham
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
| | | | - Dirk Steinke
- Centre for Biodiversity Genomics, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Paul D.N. Hebert
- Centre for Biodiversity Genomics, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Ángel Valdés
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA 91768, USA
| | - Russell C. Wyeth
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
- Biology Department, St Francis Xavier University, 2321 Notre Dame Avenue, Antigonish, NS B2G 2W5, Canada
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Nikitin VP, Solntseva SV, Kozyrev SA, Nikitin PV, Shevelkin AV. NMDA or 5-HT receptor antagonists impair memory reconsolidation and induce various types of amnesia. Behav Brain Res 2018; 345:72-82. [PMID: 29499285 DOI: 10.1016/j.bbr.2018.02.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 02/10/2018] [Accepted: 02/26/2018] [Indexed: 12/12/2022]
Abstract
Elucidation of amnesia mechanisms is one of the central problems in neuroscience with immense practical application. Previously, we found that conditioned food presentation combined with injection of a neurotransmitter receptor antagonist or protein synthesis inhibitor led to amnesia induction. In the present study, we investigated the time course and features of two amnesias: induced by impairment of memory reconsolidation using an NMDA glutamate receptor antagonist (MK-801) and a serotonin receptor antagonist (methiothepin, MET) on snails trained with food aversion conditioning. During the early period of amnesia (<10th day), the unpaired presentation of conditioned stimuli (CS) or unconditioned stimuli (US) in the same training context did not have an effect on both types of amnesia. Retraining an on 1st or 3rd day of amnesia induction facilitated memory formation, i.e. the number of CS + US pairings was lower than at initial training. On the 10th or 30th day after the MET/reminder, the number of CS + US pairings did not change between initial training and retraining. Retraining on the 10th or 30th day following the MK-801/reminder in the same or a new context of learning resulted in short, but not long-term, memory, and the number of CS + US pairings was higher than at the initial training. This type of amnesia was specific to the CS we used at initial training, since long-term memory for another kind of CS could be formed in the same snails. The attained results suggest that disruption of memory reconsolidation using antagonists of serotonin or NMDA glutamate receptors induced amnesias with different abilities to form long-term memory during the late period of development.
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Affiliation(s)
- V P Nikitin
- P.K. Anokhin Institute of Normal Physiology, Moscow, Russian Federation.
| | - S V Solntseva
- P.K. Anokhin Institute of Normal Physiology, Moscow, Russian Federation
| | - S A Kozyrev
- P.K. Anokhin Institute of Normal Physiology, Moscow, Russian Federation
| | - P V Nikitin
- P.K. Anokhin Institute of Normal Physiology, Moscow, Russian Federation; Burdenko Neurosurgical Institute, Moscow, Russian Federation
| | - A V Shevelkin
- Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, MD
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Bogodvid TK, Andrianov VV, Deryabina IB, Muranova LN, Silantyeva DI, Vinarskaya A, Balaban PM, Gainutdinov KL. Responses of Withdrawal Interneurons to Serotonin Applications in Naïve and Learned Snails Are Different. Front Cell Neurosci 2017; 11:403. [PMID: 29311833 PMCID: PMC5735116 DOI: 10.3389/fncel.2017.00403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 12/04/2017] [Indexed: 02/04/2023] Open
Abstract
Long-term changes in membrane potential after associative training were described previously in identified premotor interneurons for withdrawal of the terrestrial snail Helix. Serotonin was shown to be a major transmitter involved in triggering the long-term changes in mollusks. In the present study we compared the changes in electrophysiological characteristics of identifiable premotor interneurons for withdrawal in response to bath applications of serotonin (5-HT) or serotonin precursor 5-hydroxytryptophan (5-HTP) in preparations from naïve, neurotoxin-injected or associatively trained snails. It was found that 5-HT or 5-HTP applications caused a significant decrease of membrane potential in premotor interneurons of naïve snails, associatively trained snails and snails with impaired serotonergic system by injection of a selective neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) 1 week before the experiments. Applications of 5-HT or 5-HTP did not cause significant changes in the action potential (AP) threshold potential of these neurons in naïve snails. Conversely, applications of 5-HT or 5-HTP to the premotor interneurons of previously trained or 5,7-DHT-injected snails caused a significant increase in the firing threshold potential in spite of a depolarizing shift of the resting membrane potential. Results demonstrate that responsiveness of premotor interneurons to extracellularly applied 5-HT or 5-HTP changes for days after the associative training or serotonin depletion. Similarity of the effects in trained and 5,7-DHT-injected animals may be due to massive release of serotonin elicited by 5,7-DHT injection. Our results suggest that serotonin release due to aversive conditionining or elicited by the neurotoxin administration triggers similar changes in resting membrane potential and AP threshold in response to bath applications of 5-HT or its precursor 5-HTP.
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Affiliation(s)
- Tatiana K. Bogodvid
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- Department of Biomedical Sciences, Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia
| | - Vyatcheslav V. Andrianov
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Irina B. Deryabina
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Lyudmila N. Muranova
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Dinara I. Silantyeva
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Aliya Vinarskaya
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel M. Balaban
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Khalil L. Gainutdinov
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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Delamater AR, Schneider K, Derman RC. Extinction of specific stimulus-outcome (S-O) associations in Pavlovian learning with an extended CS procedure. JOURNAL OF EXPERIMENTAL PSYCHOLOGY. ANIMAL LEARNING AND COGNITION 2017; 43:243-261. [PMID: 28471226 PMCID: PMC5500415 DOI: 10.1037/xan0000138] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Three experiments with male and female rats were conducted to examine the effects of Pavlovian extinction training on Pavlovian-to-instrumental transfer (PIT) in a task in which the unconditioned stimulus (US) was presented at an early time point within an extended conditioned stimulus (CS). Two instrumental responses were trained with different reinforcing outcomes (R1-O1, R2-O2) and then, independently, 2 stimuli were trained with those outcomes (S1-O1, S2-O2). One group then underwent an extinction treatment (S1-, S2-) and a second was merely exposed to the experimental contexts without any stimulus events. Finally, the effects of the 2 stimuli on instrumental responding were assessed in PIT tests. Across experiments we varied the number of Pavlovian training trials prior to extinction (8, 16, or 64 trials) and the length of time following extinction prior to test (i.e., 1 or 21 days, in a test for spontaneous recovery). We observed that outcome-specific PIT was reduced by extinction in all of our training conditions and that this extinction effect was durable, surviving a 3-week spontaneous recovery interval even though conditioned magazine approach spontaneously recovered over this interval. Although extinction reduced the magnitude of PIT, the temporal expression of PIT was mostly unaffected. We found these effects in both male and female rats, though in 1 study females were extinction-resistant. These data suggest that under the conditions studied here Pavlovian extinction may permanently weaken the ability of Pavlovian cues to retrieve a representation of their associated outcomes without impacting the temporal organization of responding. This suggests that different features of learning may be differentially sensitive to extinction. (PsycINFO Database Record
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Affiliation(s)
- Andrew R Delamater
- Department of Psychology, Brooklyn College of the City University of New York
| | - Kevin Schneider
- Department of Psychology, Brooklyn College of the City University of New York
| | - Rifka C Derman
- Department of Psychology, Brooklyn College of the City University of New York
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Abstract
Primary headache is a common malady that is often under-recognized and frequently inadequately managed in spite of the fact that it affects up to 95 % of the population in a lifetime. Many forms of headache, including episodic tension and migraine headaches, if properly diagnosed, are reasonably amenable to treatment, but a smaller, though not insignificant, percent of the population suffer daily from a chronic, intractable form of headache that destroys one's productivity and quality of life. These patients are frequently seen in neurological practices at a point when treatment options are limited and largely ineffective. In the following review, we will discuss mechanisms drawn from recent studies that address the transition from acute to chronic pain that may apply to the transformation from episodic to chronic daily headaches which may offer opportunities for preempting headache transformation.
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Andrianov VV, Bogodvid TK, Deryabina IB, Golovchenko AN, Muranova LN, Tagirova RR, Vinarskaya AK, Gainutdinov KL. Modulation of defensive reflex conditioning in snails by serotonin. Front Behav Neurosci 2015; 9:279. [PMID: 26557063 PMCID: PMC4615812 DOI: 10.3389/fnbeh.2015.00279] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 10/02/2015] [Indexed: 01/24/2023] Open
Abstract
Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the "neurotoxic" analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the "neurotoxic" analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed. We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the "neurotoxic" analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3.
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Affiliation(s)
- Vyatcheslav V. Andrianov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Group of Biophysics, Zavoisky Physical-Technical Institute, Russian Academy of SciencesKazan, Russia
| | - Tatiana K. Bogodvid
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Department of Biomedical Sciences, Volga Region State Academy of Physical Culture, Sport and TourismKazan, Russia
| | - Irina B. Deryabina
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Aleksandra N. Golovchenko
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Lyudmila N. Muranova
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Roza R. Tagirova
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Aliya K. Vinarskaya
- Laboratory of Cellular Neurobiology of Learning, Institute of High Nerve Activity and Neurophysiology, Russian Academy of SciencesMoscow, Russia
| | - Khalil L. Gainutdinov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Group of Biophysics, Zavoisky Physical-Technical Institute, Russian Academy of SciencesKazan, Russia
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Kasheverov IE, Shelukhina IV, Kudryavtsev DS, Makarieva TN, Spirova EN, Guzii AG, Stonik VA, Tsetlin VI. 6-bromohypaphorine from marine nudibranch mollusk Hermissenda crassicornis is an agonist of human α7 nicotinic acetylcholine receptor. Mar Drugs 2015; 13:1255-66. [PMID: 25775422 PMCID: PMC4377982 DOI: 10.3390/md13031255] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 01/07/2023] Open
Abstract
6-Bromohypaphorine (6-BHP) has been isolated from the marine sponges Pachymatisma johnstoni, Aplysina sp., and the tunicate Aplidium conicum, but data on its biological activity were not available. For the nudibranch mollusk Hermissenda crassicornis no endogenous compounds were known, and here we describe the isolation of 6-BHP from this mollusk and its effects on different nicotinic acetylcholine receptors (nAChR). Two-electrode voltage-clamp experiments on the chimeric α7 nAChR (built of chicken α7 ligand-binding and glycine receptor transmembrane domains) or on rat α4β2 nAChR expressed in Xenopus oocytes revealed no action of 6-BHP. However, in radioligand analysis, 6-BHP competed with radioiodinated α-bungarotoxin for binding to human α7 nAChR expressed in GH4C1 cells (IC50 23 ± 1 μM), but showed no competition on muscle-type nAChR from Torpedo californica. In Ca2+-imaging experiments on the human α7 nAChR expressed in the Neuro2a cells, 6-BHP in the presence of PNU120596 behaved as an agonist (EC50 ~80 μM). To the best of our knowledge, 6-BHP is the first low-molecular weight compound from marine source which is an agonist of the nAChR subtype. This may have physiological importance because H. crassicornis, with its simple and tractable nervous system, is a convenient model system for studying the learning and memory processes.
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Affiliation(s)
- Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, Moscow 117997, Russia.
| | - Irina V Shelukhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, Moscow 117997, Russia.
| | - Denis S Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, Moscow 117997, Russia.
| | - Tatyana N Makarieva
- Elyakov Pacific Institute of Bioorganic Chemistry (PIBOC), Russian Academy of Sciences, Prospect 100 let Vladivostoku, 159, Vladivostok 690022, Russia.
| | - Ekaterina N Spirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, Moscow 117997, Russia.
| | - Alla G Guzii
- Elyakov Pacific Institute of Bioorganic Chemistry (PIBOC), Russian Academy of Sciences, Prospect 100 let Vladivostoku, 159, Vladivostok 690022, Russia.
| | - Valentin A Stonik
- Elyakov Pacific Institute of Bioorganic Chemistry (PIBOC), Russian Academy of Sciences, Prospect 100 let Vladivostoku, 159, Vladivostok 690022, Russia.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, Moscow 117997, Russia.
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Cavallo JS, Hamilton BN, Farley J. In vitro extinction learning in Hermissenda: involvement of conditioned inhibition molecules. Front Behav Neurosci 2014; 8:354. [PMID: 25374517 PMCID: PMC4204529 DOI: 10.3389/fnbeh.2014.00354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/23/2014] [Indexed: 11/30/2022] Open
Abstract
Extinction of a conditioned association is typically viewed as the establishment of new learning rather than the erasure of the original memory. However, recent research in the nudibranch, Hermissenda crassicornis (H.c.) demonstrated that extinction training (using repeated light-alone presentations) given 15 min, but not 23 h, after memory acquisition reversed both the cellular correlates of learning (enhanced Type B cell excitability) and the behavioral changes (reduced phototaxis) produced by associative conditioning (pairings of light, CS, and rotation, US). Here, we investigated the putative molecular signaling pathways that underlie this extinction in H.c. by using a novel in vitro protocol combined with pharmacological manipulations. After intact H.c. received either light-rotation pairings (Paired), random presentations of light and rotation (Random), or no stimulation (Untrained), B cells from isolated CNSs were recorded from during exposure to extinction training consisting of two series of 15 consecutive light-steps (LSs). When in vitro extinction was administered shortly (2 h, but not 24 h) after paired training, B cells from Paired animals showed progressive and robust declines in spike frequency by the 30th LS, while control cells (Random and Untrained) did not. We found that several molecules implicated in H.c. conditioned inhibitory (CI) learning, protein phosphatase 1 (PP1) and arachidonic acid (AA)/12-lipoxygenase (12-LOX) metabolites, also contributed to the spike frequency decreases produced by in vitro extinction. Protein phosphatase 2B (PP2B) also appeared to play a role. Calyculin A (PP1 inhibitor), cyclosporin A (PP2B inhibitor), and baicalein (a 12-LOX inhibitor) all blocked the spike frequency declines in Paired B cells produced by 30 LSs. Conversely, injection of catalytically-active PP1 (caPP1) or PP2B (caPP2B) into Untrained B cells partially mimicked the spike frequency declines observed in Paired cells, as did bath-applied AA, and occluded additional LS-produced reductions in spiking in Paired cells.
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Affiliation(s)
- Joel S Cavallo
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
| | - Brittany N Hamilton
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
| | - Joseph Farley
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University Bloomington, IN, USA
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