-
Trends in Neurosciences Mar 1990
Review
Topics: Animals; Aplysia; Nervous System Physiological Phenomena; Reflex
PubMed: 1691872
DOI: 10.1016/0166-2236(90)90177-c -
Current Biology : CB Jan 2011
Topics: Animals; Aplysia; Genome; Memory; Neurons
PubMed: 21256433
DOI: 10.1016/j.cub.2010.11.028 -
Current Opinion in Neurobiology Oct 2023The activity of multifunctional networks is configured by neuromodulators that exert persistent effects. This raises a question, does this impact the ability of a... (Review)
Review
The activity of multifunctional networks is configured by neuromodulators that exert persistent effects. This raises a question, does this impact the ability of a network to switch from one type of activity to another? We review studies that have addressed this question in the Aplysia feeding circuit. Task switching in this system occurs "asymmetrically." When there is a switch from egestion to ingestion neuromodulation impedes switching (creates a "negative bias"). When there is a switch from ingestion to egestion the biasing is "positive." Ingestion promotes subsequent egestion. We contrast mechanisms responsible for the two types of biasing and show that the observed asymmetry is a consequence of the fact that there is more than one set of egestive circuit parameters.
Topics: Animals; Aplysia; Feeding Behavior
PubMed: 37625344
DOI: 10.1016/j.conb.2023.102775 -
Journal of Natural Products Aug 2022New bromoditerpenes having an α-methylene carbonyl structure, azuriaplysins A () and B (), were isolated from the sea hare . Their relative stereostructures were... (Review)
Review
New bromoditerpenes having an α-methylene carbonyl structure, azuriaplysins A () and B (), were isolated from the sea hare . Their relative stereostructures were determined based on one- and two-dimensional NMR spectroscopic analysis. In addition, the absolute stereostructures were determined by the total synthesis of both enantiomers of azuriaplysins A () and B (), the key points of which were bromocyclization of farnesol and optical resolution of a key intermediate. Azuriaplysin B () and its enantiomer exhibited moderate cytotoxicity against HeLa S3 cells.
Topics: Animals; Aplysia; Hares; Magnetic Resonance Spectroscopy; Stereoisomerism
PubMed: 35834804
DOI: 10.1021/acs.jnatprod.2c00476 -
Journal of Neurophysiology Sep 2017Many central pattern generator (CPG)-mediated behaviors are episodic, meaning that they are not continuously ongoing; instead, there are pauses between bouts of... (Review)
Review
Many central pattern generator (CPG)-mediated behaviors are episodic, meaning that they are not continuously ongoing; instead, there are pauses between bouts of activity. This raises an interesting possibility, that the neural networks that mediate these behaviors are not operating under "steady-state" conditions; i.e., there could be dynamic changes in motor activity as it stops and starts. Research in the feeding system of the mollusk has demonstrated that this can be the case. After a pause, initial food grasping responses are relatively weak. With repetition, however, responses strengthen. In this review we describe experiments that have characterized cellular/molecular mechanisms that produce these changes in motor activity. In particular, we focus on cumulative effects of modulatory neuropeptides. Furthermore, we relate research to work in other systems and species, and develop a hypothesis that postulates that changes in response magnitude are a reflection of an efficient feeding strategy.
Topics: Animals; Aplysia; Central Pattern Generators; Feeding Behavior; Movement; Repetition Priming
PubMed: 28679841
DOI: 10.1152/jn.00373.2017 -
The Biological Bulletin Jun 2006Until recently, investigations of the neurobiological substrates of simple forms of learning and memory in the marine snail Aplysia have focused mostly on plastic... (Review)
Review
Until recently, investigations of the neurobiological substrates of simple forms of learning and memory in the marine snail Aplysia have focused mostly on plastic changes that occur within the presynaptic sensory neurons. Here, I summarize the results of recent studies that indicate that exclusively presynaptic processes cannot account for simple forms of learning in Aplysia. In particular, I present evidence that postsynaptic mechanisms play a far more important role in nonassociative learning in Aplysia than has been appreciated before now. Moreover, I describe recent data that suggests the intriguing hypothesis that the persistent, learning-induced changes in Aplysia sensory neurons might depend critically on postsynaptic signals for their induction. Finally, I discuss the potential applicability of this hypothesis to learning-related synaptic plasticity in the mammalian brain.
Topics: Animals; Aplysia; Excitatory Postsynaptic Potentials; Habituation, Psychophysiologic; Learning; Models, Neurological; Neuronal Plasticity; Neurons, Afferent; Receptors, Glutamate; Synapses
PubMed: 16801500
DOI: 10.2307/4134563 -
Journal of Neuroscience Methods Apr 2022A growing body of research demonstrates that focused ultrasound stimulates activity in human and other mammalian nervous systems. However, there is no consensus on which...
BACKGROUND
A growing body of research demonstrates that focused ultrasound stimulates activity in human and other mammalian nervous systems. However, there is no consensus on which sonication parameters are optimal. Furthermore, the mechanism of action behind ultrasound neurostimulation remains poorly understood. An invertebrate model greatly reduces biological complexity, permitting a systematic evaluation of sonication parameters suitable for ultrasound neurostimulation.
NEW METHOD
Here, we describe the use of focused ultrasound stimulation with an ex-vivo abdominal ganglion preparation of the California sea hare, Aplysia californica, a long-standing model system in neurobiology. We developed a system for stimulating an isolated ganglion preparation while obtaining extracellular recordings from nerves. The focused ultrasound stimulation uses one of two single-element transducers, enabling stimulation at four distinct carrier frequencies (0.515 MHz, 1.l MHz, 1.61 MHz, 3.41 MHz).
RESULTS
Using continuous wave ultrasound, we stimulated the ganglion at all four frequencies, and we present quantitative evaluation of elicited activation at four different sonication durations and three peak pressure levels, eliciting up to a 57-fold increase in spiking frequency.
COMPARISON WITH ELECTRICAL STIMULATION
We demonstrated that ultrasound-induced activation is repeatable, and the response consistency is comparable to electrical stimulation.
CONCLUSIONS
Due to the relative ease of long-term recordings for many hours, this ex-vivo ganglion preparation is suitable for investigating sonication parameters and the effects of focused ultrasound stimulation on neurons.
Topics: Animals; Aplysia; Electric Stimulation; Humans; Mammals; Neurons; Transducers
PubMed: 35227740
DOI: 10.1016/j.jneumeth.2022.109536 -
The Biological Bulletin Jun 2006Cellular studies of implicit and explicit memory suggest that experience-dependent modulation of synaptic strength and structure is a fundamental mechanism by which... (Review)
Review
Cellular studies of implicit and explicit memory suggest that experience-dependent modulation of synaptic strength and structure is a fundamental mechanism by which these memories are encoded, processed, and stored within the brain. In this review, we focus on recent advances in our understanding of the molecular mechanisms that underlie short-term, intermediate-term, and long-term forms of implicit memory in the marine invertebrate Aplysia californica, and consider how the conservation of common elements in each form may contribute to the different temporal phases of memory storage.
Topics: Animals; Aplysia; Conditioning, Classical; Memory; Memory, Short-Term; Models, Neurological; Reflex; Synapses
PubMed: 16801493
DOI: 10.2307/4134556 -
Scientific Reports Jan 2022Neuropeptides, as pervasive intercellular signaling molecules in the CNS, modulate a variety of behavioral systems in both protostomes and deuterostomes. Allatostatins...
Neuropeptides, as pervasive intercellular signaling molecules in the CNS, modulate a variety of behavioral systems in both protostomes and deuterostomes. Allatostatins are neuropeptides in arthropods that inhibit the biosynthesis of juvenile hormones. Based on amino acid sequences, they are divided into three different types in arthropods: allatostatin A, allatostatin B, allatostatin C. Allatostatin C (AstC) was first isolated from Manduca sexta, and it has an important conserved feature of a disulfide bridge formed by two cysteine residues. Moreover, AstC appears to be the ortholog of mammalian somatostatin, and it has functions in common with somatostatin, such as modulating feeding behaviors. The AstC signaling system has been widely studied in arthropods, but minimally studied in molluscs. In this study, we seek to identify the AstC signaling system in the marine mollusc Aplysia californica. We cloned the AstC precursor from the cDNA of Aplysia. We predicted a 15-amino acid peptide with a disulfide bridge, i.e., AstC, using NeuroPred. We then cloned two putative allatostatin C-like receptors and through NCBI Conserved Domain Search we found that they belonged to the G protein-coupled receptor (GPCR) family. In addition, using an inositol monophosphate 1 (IP1) accumulation assay, we showed that Aplysia AstC could activate one of the putative receptors, i.e., the AstC-R, at the lowest EC, and AstC without the disulfide bridge (AstC') activated AstC-R with the highest EC. Moreover, four molluscan AstCs with variations of sequences from Aplysia AstC but with the disulfide bridge activated AstC-R at intermediate EC. In summary, our successful identification of the Aplysia AstC precursor and its receptor (AstC-R) represents the first example in molluscs, and provides an important basis for further studies of the AstC signaling system in Aplysia and other molluscs.
Topics: Amino Acid Sequence; Animals; Aplysia; CHO Cells; Cricetulus; Evolution, Molecular; Neuropeptides; Phylogeny
PubMed: 35075137
DOI: 10.1038/s41598-022-05071-8 -
Cold Spring Harbor Symposia on... 1990
Review
Topics: Animals; Aplysia; Cell Adhesion Molecules, Neuronal; Memory; Phosphorylation; Serotonin; Synapses; Synaptic Transmission
PubMed: 1966763
DOI: 10.1101/sqb.1990.055.01.021