The pharmacology of molluscan neurons

S.-Rózsa, Katalin

doi:10.1016/0301-0082(84)90013-3

Cited by 79 publications

(8 citation statements)

References 464 publications

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“…Glutamate is the most likely primary transmitter of vertebrate photoreceptors (for review, see Lam, 1997), and numerous investigations have suggested that it is a neurotransmitter in the molluscan central nervous system (for review, see S.‐Rózsa, 1984). Our immunocytochemical findings implicate glutamate as a putative transmitter of the large photoreceptor cells as well as of the BRNs in the eyes of the marine snail B. gouldiana .…”

Section: Resultsmentioning

confidence: 99%

Amine and amino acid transmitters in the eye of the molluscBulla gouldiana: An immunocytochemical study

2000

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We identified putative transmitters of the photoreceptors and circadian pacemaker neurons and found candidates for efferent control in the eye of the marine mollusc Bulla gouldiana. Established antisera against octopamine, dopamine, serotonin, histamine, glutamate, gamma-aminobutyric acid (GABA), and taurine were used, and central ganglia were processed in parallel to evaluate general staining quality. Photoreceptors and circadian pacemaker cells both expressed immunoreactivity for glutamate and taurine. The eye and its sheath were devoid of GABA-like immunoreactive material, and none of the antisera directed against biogenic amines labelled cells or processes in the nervous tissue of the eye. However, dopamine and octopamine antisera stained large spherical granules (diameter 2-3 microm) contained in granular cells that are located in the connective tissue encapsulating the eye and the optic nerve. The serotonin antiserum revealed a sparse distribution of varicose axon fibers in the optic nerve and eye sheath. No histamine-immunoreactive processes were revealed in the eye. The functional significance of these findings for the molluscan eye and its circadian clock is discussed.

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Section: Resultsmentioning

confidence: 99%

Amine and amino acid transmitters in the eye of the molluscBulla gouldiana: An immunocytochemical study

2000

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“…They have been detected in the central and peripheral nervous systems of diVerent pulmonate gastropods (Cooke and Gelperin 1988;Elekes and Nässel 1990;Elekes 1992;Suzuki et al 1997) and in the central nervous system and CSOs of the opisthobranchs Phestilla sibogae (Croll et al , 2003 and Aplysia californica (Elekes 1992;Wollesen et al 2007). Serotonin (5-HT) is a biogenic monoamine which is synthesized in the nervous system from the amino acid tryptophan (S.-Rozsa 1984). It has been investigated in numerous studies of the central nervous system of gastropods (Ono and McCaman 1984;Longley and Longley 1986;Hernadi et al 1989;Elekes 1992;Sudlow et al 1998;Hernadi and Elekes 1999;Croll et al 2001;Shirahata et al 2004;Newcomb et al 2006;Hochberg 2007) and the CSOs of a variety of opisthobranchs (Moroz et al 1997;Croll et al 2003;Wertz et al 2006Wertz et al , 2007Hochberg 2007;Wollesen et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…TH is an enzyme which catalyses the initial step in the conversion of tyrosine to the catecholamines (S. -Rozsa 1984), and therefore indicative of catecholamines. Catecholamines have been detected in the central nervous systems of diVerent pulmonate gastropods (Elekes et al 1991;Hernadi et al 1993;Hernadi and Elekes 1999), in the central and peripheral nervous systems of the opisthobranchs Aplysia depilans, Aplysia fasciata and Aplysia californica (Salimova et al 1987;Croll 2001) and in the central nervous system and CSOs of the opisthobranch Phestilla sibogae (Croll et al , 2003.…”

Section: Introductionmentioning

confidence: 99%

Comparative immunohistochemistry of the cephalic sensory organs in Opisthobranchia (Mollusca, Gastropoda)

2008

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The structure and function of the central nervous systems of opisthobranch gastropods have been studied extensively. However, the organisation and function of the peripheral nervous system are poorly understood. The cephalic sensory organs (CSOs) are known to be chemosensory structures in the head region of opisthobranchs. In the present study, we used immunohistochemical methods and confocal laserscanning microscopy to comparatively examine the CSOs of diVerent opisthobranchs, namely Acteon tornatilis, Aplysia punctata, Archidoris pseudoargus and Haminoea hydatis. We wanted to characterise sensory epithelia in order to infer the function of sensory structures and the organs they constitute. Immunoreactivity against the three antigens tyrosine hydroxylase, FMRFamide and serotonin was very similar in the CSOs of all investigated species. Tyrosine hydroxylase-like immunoreactivity was detected primarily in subepidermal sensory cell bodies, which were much more abundant in the anteriorly situated CSOs. This observation indicates that these cells and the respective organs may be involved in contact chemoreception and mechanoreception. The dominant features of FMRFamide-like immunoreactivity, especially in the posterior CSOs, were tightly knotted Wbres which reveal glomerulus-like structures. This suggests an olfactory role for these organs. Serotonin-like immunoreactivity was detected in an extensive network of eVerent Wbres, but was not found within any peripheral cell bodies. Serotonin-like immunoreactivity was found in the same glomerulus-like structures as FMRFamide-like immunoreactivity, indicating a function of serotonin in the eVerent control of olfactory inputs. Besides this functional implication, this study could also add some knowledge on the doubtful homology of the CSOs in opisthobranch gastropods.

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“…Certainly, previous pharmacological characterization of receptors for various signaling molecules in mollusks (reviewed by S. -Rozsa, 1984) would predict separate receptors for each modulator family-the SCPs, the MMs, and 5-HT-though probably not for different members of the same family (but see the following article, BPezina et al, 1994d). Moreover, Lloyd et al (1984) observed some additivity between even maximal effects of 5-HT and SCP, on CAMP levels in the ARC muscle, sug- A, Holding-potential dependence.…”

Section: Receptor Pharmacologymentioning

confidence: 99%

Enhancement of Ca current in the accessory radula closer muscle of Aplysia californica by neuromodulators that potentiate its contractions

1994

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A major goal of neuroscience is to identify the neural and cellular mechanisms of behavior and its plasticity. Progress toward this goal has come particularly from work with a small number of tractable model preparations. One of these is the simple neuromuscular circuit consisting of the accessory radula closer (ARC) muscle of the mollusk Aplysia californica and its innervating motor and modulatory neurons. Contraction of the ARC muscle underlies a component of Aplysia feeding behavior, and plasticity of the behavior is in large part due to modulation of the amplitude and duration of the contractions of the muscle by a variety of modulatory neurotransmitters and peptide cotransmitters, among them the small cardioactive peptides (SCPs), myomodulins (MMs), and serotonin (5-HT). We have studied single dissociated ARC muscle fibers in order to determine whether modulation of membrane ion currents in the muscle might underlie these effects. First, we confirmed that the dissociated fibers were functionally intact: just as with the whole ARC muscle, their contractions were potentiated by 5-HT and SCPB and potentiated as well as depressed by MMA, and their cAMP content was greatly elevated by 5-HT, SCPA and SCPB, and to a lesser extent by MMA and MMB. Next, using voltage-clamp techniques, we found that two ion currents present in the fibers were indeed modulated. The fibers possess a dihydropyridine-sensitive, high- threshold “L”-type Ca current. This current was enhanced by the modulators that potentiate ARC-muscle contractions--5-HT, SCPA and SCPB, and MMA and MMB--but not by buccalinA, a modulator that does not act directly on the ARC muscle. All of the potentiating modulators, as well as elevation of cAMP in the fibers by forskolin or a cAMP analog, maximally enhanced the current about twofold and mutually occluded each other's effects. Since the Ca current supplies Ca2+ necessary for contraction of the muscle, the enhancement of the current is a good candidate to be a major mechanism of the potentiation of the contractions. In the following article we report that the modulators also, to different degrees, activate a distinctive K current and thereby depress the contractions. Net potentiation or depression then depends on the balance between the relative strengths of the modulation of the two ion currents.

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The pharmacology of molluscan neurons

Cited by 79 publications

References 464 publications

Amine and amino acid transmitters in the eye of the molluscBulla gouldiana: An immunocytochemical study

Amine and amino acid transmitters in the eye of the molluscBulla gouldiana: An immunocytochemical study

Comparative immunohistochemistry of the cephalic sensory organs in Opisthobranchia (Mollusca, Gastropoda)

Enhancement of Ca current in the accessory radula closer muscle of Aplysia californica by neuromodulators that potentiate its contractions

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