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Browning H, Birch J. Animal sentience. PHILOSOPHY COMPASS 2022; 17:e12822. [PMID: 35859762 PMCID: PMC9285591 DOI: 10.1111/phc3.12822] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 10/01/2021] [Accepted: 02/14/2022] [Indexed: 06/01/2023]
Abstract
'Sentience' sometimes refers to the capacity for any type of subjective experience, and sometimes to the capacity to have subjective experiences with a positive or negative valence, such as pain or pleasure. We review recent controversies regarding sentience in fish and invertebrates and consider the deep methodological challenge posed by these cases. We then present two ways of responding to the challenge. In a policy-making context, precautionary thinking can help us treat animals appropriately despite continuing uncertainty about their sentience. In a scientific context, we can draw inspiration from the science of human consciousness to disentangle conscious and unconscious perception (especially vision) in animals. Developing better ways to disentangle conscious and unconscious affect is a key priority for future research.
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Affiliation(s)
- Heather Browning
- Centre for Philosophy of Natural and Social ScienceLondon School of Economics and Political ScienceLondonUK
| | - Jonathan Birch
- Centre for Philosophy of Natural and Social ScienceLondon School of Economics and Political ScienceLondonUK
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Sumra K, Stahlman WD. A non-selective serotonin antagonist promotes rapid habituation in the terrestrial hermit crab. Saudi J Biol Sci 2019; 26:1621-1625. [PMID: 31762636 PMCID: PMC6864153 DOI: 10.1016/j.sjbs.2018.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 09/17/2018] [Accepted: 09/25/2018] [Indexed: 11/11/2022] Open
Abstract
Research has indicated that serotonin (5-HT) modulates non-associative learning in a variety of invertebrate species. Recent work has demonstrated that the terrestrial hermit crab is a suitable animal model for non-associative learning phenomena, including habituation, sensitization, and dishabituation. We examined the potential role of a non-selective 5-HT antagonist, methysergide, in non-associative learning in the hermit crab. We administered methysergide prior to delivering repeated stimulus presentations of a looming visual predator. We found evidence for more rapid habituation relative to a control condition in which crabs did not receive the drug. These results indicate a role for 5-HT in the defensive behavior of the hermit crab and importantly, suggest a conserved role for 5-HT in modulating basic learning processes in invertebrates.
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Affiliation(s)
- Kirandeep Sumra
- Department of Psychology, University of California, Los Angeles, USA
| | - W David Stahlman
- Department of Psychology, University of California, Los Angeles, USA
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Inohara ETS, Pinto CB, Model JFA, Trapp M, Kucharski LC, Da Silva RSM, Vinagre AS. Serotonin effects in the crab Neohelice granulata: Possible involvement of two types of receptors in peripheral tissues. Comp Biochem Physiol A Mol Integr Physiol 2015; 185:80-90. [DOI: 10.1016/j.cbpa.2015.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
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Perry CJ, Barron AB, Cheng K. Invertebrate learning and cognition: relating phenomena to neural substrate. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2013; 4:561-582. [PMID: 26304245 DOI: 10.1002/wcs.1248] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/28/2013] [Accepted: 07/06/2013] [Indexed: 02/04/2023]
Abstract
Diverse invertebrate species have been used for studies of learning and comparative cognition. Although we have gained invaluable information from this, in this study we argue that our approach to comparative learning research is rather deficient. Generally invertebrate learning research has focused mainly on arthropods, and most of that within the Hymenoptera and Diptera. Any true comparative analysis of the distribution of comparative cognitive abilities across phyla is hampered by this bias, and more fundamentally by a reporting bias toward positive results. To understand the limits of learning and cognition for a species, knowing what animals cannot do is at least as important as reporting what they can. Finally, much more effort needs to be focused on the neurobiological analysis of different types of learning to truly understand the differences and similarities of learning types. In this review, we first give a brief overview of the various forms of learning in invertebrates. We also suggest areas where further study is needed for a more comparative understanding of learning. Finally, using what is known of learning in honeybees and the well-studied honeybee brain, we present a model of how various complex forms of learning may be accounted for with the same neural circuitry required for so-called simple learning types. At the neurobiological level, different learning phenomena are unlikely to be independent, and without considering this it is very difficult to correctly interpret the phylogenetic distribution of learning and cognitive abilities. WIREs Cogn Sci 2013, 4:561-582. doi: 10.1002/wcs.1248 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Clint J Perry
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Andrew B Barron
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ken Cheng
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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Minoli S, Palottini F, Manrique G. The main component of an alarm pheromone of kissing bugs plays multiple roles in the cognitive modulation of the escape response. Front Behav Neurosci 2013; 7:77. [PMID: 23847483 PMCID: PMC3701871 DOI: 10.3389/fnbeh.2013.00077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
Innate responses in animals can be modulated by experience. Disturbed adults of the triatomine bug Triatoma infestans release an alarm pheromone (AP) that elicits an escape response in conspecific larvae. The main component of this AP, the isobutyric acid (IsoAc), alone has already shown to generate an escape response in this species. However, not much is known about the modulation of this behavior by non-associative and associative cognitive processes. We present here evidences of the cognitive capacities of T. infestans larvae in an escape context under different conditioning paradigms, including IsoAc in different roles. We show that: (1) the duration of a pre-exposure to IsoAc plays a main role in determining the type of non-associative learning expressed: short time pre-exposures elicit a sensitization while a longer pre-exposure time triggers a switch from repellence to attractiveness; (2) a simple pre-exposure event is enough to modulate the escape response of larvae to the AP and to its main component: IsoAc; (3) IsoAc and the AP are perceived as different chemical entities; (4) an association between IsoAc and an aversive stimulus can be created under a classical conditioning paradigm; (5) an association between IsoAc and a self-action can be generated under an operant conditioning. These results evince that IsoAc can attain multiple and different cognitive roles in the modulation of the escape response of triatomines and show how cognitive processes can modulate a key behavior for surviving, as it is the escaping response in presence of a potential danger in insects.
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Affiliation(s)
- Sebastian Minoli
- Laboratorio de Fisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IBBEA, CONICET-UBA Buenos Aires, Argentina
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A Multidisciplinary Approach to Learning and Memory in the Crab Neohelice (Chasmagnathus) granulata. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-415823-8.00026-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Aquiloni L, Giulianini PG, Mosco A, Guarnaccia C, Ferrero E, Gherardi F. Crustacean hyperglycemic hormone (cHH) as a modulator of aggression in crustacean decapods. PLoS One 2012; 7:e50047. [PMID: 23166815 PMCID: PMC3500340 DOI: 10.1371/journal.pone.0050047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 10/19/2012] [Indexed: 11/18/2022] Open
Abstract
Biogenic amines, particularly serotonin, are recognised to play an important role in controlling the aggression of invertebrates, whereas the effect of neurohormones is still underexplored. The crustacean Hyperglycemic Hormone (cHH) is a multifunctional member of the eyestalk neuropeptide family. We expect that this neuropeptide influences aggression either directly, by controlling its expression, or indirectly, by mobilizing the energetic stores needed for the increased activity of an animal. Our study aims at testing such an influence and the possible reversion of hierarchies in the red swamp crayfish, Procambarus clarkii, as a model organism. Three types of pairs of similarly sized males were formed: (1) 'control pairs' (CP, n = 8): both individuals were injected with a phosphate saline solution (PBS); (2) 'reinforced pairs' (RP, n = 9): the alpha alone was injected with native cHH, and the beta with PBS; (3) 'inverted pairs' (IP, n = 9): the opposite of (2). We found that, independently of the crayfish's prior social experience, cHH injections induced (i) the expression of dominance behaviour, (ii) higher glycemic levels, and (iii) lower time spent motionless. In CP and RP, fight intensity decreased with the establishment of dominance. On the contrary, in IP, betas became increasingly likely to initiate and escalate fights and, consequently, increased their dominance till a temporary reversal of the hierarchy. Our results demonstrate, for the first time, that, similarly to serotonin, cHH enhances individual aggression, up to reverse, although transitorily, the hierarchical rank. New research perspectives are thus opened in our intriguing effort of understanding the role of cHH in the modulation of agonistic behaviour in crustaceans.
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Affiliation(s)
- Laura Aquiloni
- Dipartimento di Biologia Evoluzionistica Leo Pardi, Università degli Studi di Firenze, Firenze, Italy.
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Fathala MDV, Iribarren L, Kunert MC, Maldonado H. A field model of learning: 1. Short-term memory in the crab Chasmagnathus granulatus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2009; 196:61-75. [DOI: 10.1007/s00359-009-0494-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 11/27/2009] [Accepted: 11/28/2009] [Indexed: 11/29/2022]
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9
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Tricarico E, Gherardi F. Biogenic amines influence aggressiveness in crayfish but not their force or hierarchical rank. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2007.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Zaccardi ML, Traina G, Cataldo E, Brunelli M. Sensitization and dishabituation of swim induction in the leech Hirudo medicinalis: role of serotonin and cyclic AMP. Behav Brain Res 2004; 153:317-26. [PMID: 15265626 DOI: 10.1016/j.bbr.2003.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Revised: 12/09/2003] [Accepted: 12/10/2003] [Indexed: 10/26/2022]
Abstract
In this paper the role of serotonin (5HT) and cyclic AMP (cAMP) in sensitization and dishabituation of swim induction (SI) has been investigated in the leech Hirudo medicinalis. Electrical stimulation of the body wall evokes swimming activity with a constant latency. In animals with a disconnection between head ganglion and segmental ganglia, repetitive stimulation induces habituation of swimming whereas brushing on the dorsal skin provokes sensitization of a naïve response or dishabituation of a previously habituated response. Our findings indicate that 5HT is the neurotransmitter underlying both sensitization and dishabituation of SI. Injection of the 5HT receptor blocking agent methysergide impaires the onset of sensitization and dishabituation induced by brushing. Moreover, injection of 5HT mimics these forms of nonassociative learning, whereas injection of dopamine does not. Finally, the effects of 5HT are mediated by cAMP: (1) after injections of specific adenylate cyclase inhibitors such as MDL 12.330A or SQ22536, brushing becomes ineffective in facilitating the SI in either non-habituated or habituated animals. (2) 8Br-cAMP application mimics both sensitization and dishabituation of SI.
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Affiliation(s)
- Maria Luisa Zaccardi
- Dipartimento di Fisiologia e Biochimica G. Moruzzi, Università degli Studi di Pisa, Via S. Zeno 31, 56127 Pisa, Italy
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Poulin R, Nichol K, Latham ADM. Host sharing and host manipulation by larval helminths in shore crabs: cooperation or conflict? Int J Parasitol 2003; 33:425-33. [PMID: 12705935 DOI: 10.1016/s0020-7519(03)00002-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Larval helminths of different species that share the same intermediate host and are transmitted by predation to the same definitive host may cooperate in their attempts to manipulate the behaviour of the intermediate host, while at the same time having conflicts of interests over the use of host resources. A few studies have indicated that intermediate hosts harbouring larval helminths have altered concentrations of neurotransmitters in their nervous system, and thus measuring levels of neurotransmitters in host brains could serve to assess the respective and combined effect of different helminth species on host behaviour. Here, we investigate potential cooperation and conflict among three helminths in two species of crab intermediate hosts. The acanthocephalan Profilicollis spp., the trematode Maritrema sp. and an acuariid nematode, all use Macrophthalmus hirtipes (Ocypodidae) as intermediate host, whereas Profilicollis and Maritrema also use Hemigrapsus crenulatus (Grapsidae). All three helminths mature inside gulls or other shore birds. There was a significant decrease in the mean volume of Profilicollis cystacanths as the intensity of infection by this parasite increased in H. crenulatus, the only host in which this was investigated; however, there was no measurable effect of other helminth species on the size of acanthocephalans, suggesting no interspecific conflict over resource use within crabs. There was, in contrast, evidence of a positive interspecific association between the two most common helminth species: numbers of Profilicollis and Maritrema were positively correlated among crabs, independently of crab size, in M. hirtipes but not H. crenulatus. More importantly, we found that the total number of larval helminths per crab correlated significantly, and negatively, with concentrations of serotonin in crab brains, again only in M. hirtipes; numbers of each parasite species separately did not covary in either crab species with serotonin or dopamine, the other neurotransmitter investigated in this study. The relationship with serotonin appears due mainly to numbers of Profilicollis and Maritrema and not to nematodes. This is the first demonstration of a potentially synergistic manipulation of host behaviour by different helminth species, one that appears host-specific; our results also point toward the neurobiological mechanism underlying this phenomenon.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
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Troncoso J, Maldonado H. Two related forms of memory in the crab Chasmagnathus are differentially affected by NMDA receptor antagonists. Pharmacol Biochem Behav 2002; 72:251-65. [PMID: 11900795 DOI: 10.1016/s0091-3057(01)00779-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A visual danger stimulus (VDS) elicits an escape response in the crab Chasmagnathus that declines after a few iterative presentations. Long-lasting retention of such decrement, termed context-signal memory (CSM), is mediated by an association between danger stimulus and environmental cues, cycloheximide sensitive, correlated with PKA activity and NFkappa-B activation, positively modulated by angiotensins, and selectively regulated by a muscarinic-cholinergic mechanism. The present research was aimed at studying the possible involvement of NMDA-like receptors in CSM, given the role attributed to these receptors in vertebrate memory and their occurrence in invertebrates including crustaceans. Vertebrate antagonists (+/-)-2-amino-5-phosphonopentanoic acid (AP5) and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) were used. Memory retention impairment was shown with MK-801 10(-3) M (1 microg/g) injected immediately before training or after training, or delayed 1 or 4 h, but not 6 h, posttraining. An AP5 10(-3) M dose (0.6 microg/g) impairs retention when given before but not after training. Neither antagonist produced retrieval deficit. A memory process similar to CSM but nonassociative in nature and induced by massed training (termed signal memory, SM), proved entirely insensitive to AP5 or MK-801, confirming the view that distinct mechanisms subserve these different types of memory in the crab.
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Affiliation(s)
- Julieta Troncoso
- Laboratorio de Neurobiología de la Memoria, Facultad de Ciencias Exactas y Naturales, Departamento Biologia, Universidad de Buenos Aires, Buenos Aires, Argentina
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Berón de Astrada M, Maldonado H. Two related forms of long-term habituation in the crab Chasmagnathus are differentially affected by scopolamine. Pharmacol Biochem Behav 1999; 63:109-18. [PMID: 10340530 DOI: 10.1016/s0091-3057(98)00256-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An opaque screen moving overhead elicits an escape response in the crab Chasmagnathus, which, after a few presentations, habituates for a long period (long-term habituation, LTH). Previous results distinguished two types of LTH: the (context-signal)-LTH yielded by spaced training, determined by an association between context and habituating stimulus, and cycloheximide sensitive: and the (signal)-LTH produced by massed training, context independent, and cycloheximide insensitive. Present experiments were aimed at studying the possible involvement of cholinergic mechanisms in one or both types of LTH, using the muscarinic antagonist, scopolamine (SCP). Results indicate that LTH acquired by spaced training (30 trials separated by 85 s) is blocked in a dose-dependent manner by posttraining SCP. Amnesia is shown with 100 ng SCP/g injected immediately before or after spaced training but not delayed 1-h posttraining. No effect of SCP on LTH acquired by massed training (300 trials separated by 4 s) is detected. Pretraining SCP induces a decrease in the response level at the initial trials of either a spaced or a massed training. It is concluded that the storage of (context-signal)-LTH may be selectively regulated by a muscarinic-cholinergic mechanism. However, the possibility that other cholinergic receptors would be involved in the consolidation of the (signal)-LTH is discussed.
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Affiliation(s)
- M Berón de Astrada
- Facultad de Ciencias Exactas y Naturales, Depto. Biología, Universidad de Buenos Aires, Argentina
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Tomsic D, Romano A, Maldonado H. Behavioral and mechanistic bases of long-term habituation in the crab Chasmagnathus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 446:17-35. [PMID: 10079835 DOI: 10.1007/978-1-4615-4869-0_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- D Tomsic
- Facultad de Ciencias Exactas y Naturales, Depto Biología, Universidad de Buenos Aires, Argentina.
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Maldonado H, Romano A, Tomsic D. Long-term habituation (LTH) in the crab Chasmagnathus: a model for behavioral and mechanistic studies of memory. Braz J Med Biol Res 1997; 30:813-26. [PMID: 9361704 DOI: 10.1590/s0100-879x1997000700001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A decade of studies on long-term habituation (LTH) in the crab Chasmagnathus is reviewed. Upon sudden presentation of a passing object overhead, the crab reacts with an escape response that habituates promptly and for at least five days. LTH proved to be an instance of associative memory and showed context, stimulus frequency and circadian phase specificity. A strong training protocol (STP) (> or = 15 trials, intertrial interval (ITI) of 171 s) invariably yielded LTH, while a weak training protocol (WTP) (< or = 10 trials, ITI = 171 s) invariably failed. STP was used with a presumably amnestic agent and WTP with a presumably hypermnestic agent. Remarkably, systemic administration of low doses was effective, which is likely to be due to the lack of an endothelial blood-brain barrier. LTH was blocked by inhibitors of protein and RNA synthesis, enhanced by protein kinase A (PKA) activators and reduced by PKA inhibitors, facilitated by angiotensin II and IV and disrupted by saralasin. The presence of angiotensins and related compounds in the crab brain was demonstrated. Diverse results suggest that LTH includes two components: an initial memory produced by spaced training and mainly expressed at an initial phase of testing, and a retraining memory produced by massed training and expressed at a later phase of testing (retraining). The initial memory would be associative, context specific and sensitive to cycloheximide, while the retraining memory would be nonassociative, context independent and insensitive to cycloheximide.
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Affiliation(s)
- H Maldonado
- Facultad de Ciencias Exactas y Naturales, Departamento de Biología, Universidad de Buenos Aires, Argentina.
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Romano A, Locatelli F, Delorenzi A, Pedreira ME, Maldonado H. Effects of activation and inhibition of cAMP-dependent protein kinase on long-term habituation in the crab Chasmagnathus. Brain Res 1996; 735:131-40. [PMID: 8905178 DOI: 10.1016/0006-8993(96)00584-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
On sudden presentation of a danger stimulus, the crab Chasmagnathus elicits an escape response that habituates promptly and for a long period. We have previously reported that administration of a cAMP-permeable analog (CPT-cAMP) along with a phosphodiesterase inhibitor (IBMX) improves long-term habituation (LTH). In present experiments we studied the effect of systemic administration of the protein kinase A (PKA) activator Sp-5,6-DCl-cBIMPS and that of the PKA inhibitor Rp-8-Cl-cAMPS on LTH tested 24 h after a weak training protocol (5 trials of danger stimulus presentation) or a strong training protocol (15-30 trials), respectively. A 50 microliters pre-training injection of 75 microM Sp-5,6-DCl-cBIMPS, and to a lesser degree of 25 microM, improved retention of the habituated response but not affect short-term habituation (STH). Like pre-training injection, post-training administration of Sp-5,6-DCl-cBIMPS proved to exert a facilitatory action on retention though with 75 microM dose only. Conversely, both pre- and post-training injection of 25 microM Rp-8-Cl-cAMPS impaired LTH without affecting STH. Thus, the PKA activator Sp-5,6-DCl-cBIMPS enables a weak training to produce LTH while the PKA inhibitor Rp-8-Cl-cAMPS impairs LTH when a strong training is given. Activation of crab PKA by Sp-5,6-DCl-cBIMPS and its inhibition by Rp-8-Cl-cAMPS were assessed using an in vitro PKA activity assay. These results provide independent evidences supporting the view that PKA plays a key role in long-term memory storage in this learning paradigm.
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Affiliation(s)
- A Romano
- Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias Biológicas, Pab 2. University of Buenos Aires, Argentina.
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Delorenzi A, Pedreira ME, Romano A, Garcia SI, Pirola CJ, Nahmod VE, Maldonado H. Angiotensin II enhances long-term memory in the crab Chasmagnathus. Brain Res Bull 1996; 41:211-20. [PMID: 8924030 DOI: 10.1016/s0361-9230(96)00178-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An opaque screen moving overhead provokes an escape response in the crab Chasmagnathus granulatus that habituates after a few presentations of the eliciting stimulus. Fifteen trials with a 180-s intertrial interval or 30 trials with a 90-s interval (strong training protocol) ensures long-term habituation (LTH) of the response for 24 h, whereas 10 trials (weak training protocol) fail to induce it. However, robust LTH is obtained when crabs are injected with human angiotensin (All; 50 pmol) immediately after a weak training protocol. This memory-enhancing effect of All is dose-dependent, reversible by saralasin (5 pmol), and vanishes either when the weak training protocol is reduced to only five trials, or when the peptide is given before training or 1 h after. LTH is impaired by saralasin (5 pmol) administered before or after the strong training protocol, but no amnestic effect is disclosed when the antagonist is given 1 h after. On the other hand, both All-like immunoreactivity and angiotensin-converting enzyme-like activity are described in diverse tissues of Chasmagnathus, namely, in gills and in both thoracic and supraesophageal ganglia. Results support the view that some components of the renin-angiotensin system and their influence on memory might have emerged early in evolution.
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Affiliation(s)
- A Delorenzi
- Laboratorio de Sustancias Vasoactivas, Facultad de Medicina, Universidad de Buenos Aires, Argentina
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