Psychiatry related information on Hermissenda

• Specifically, activation of PKC mimics neurobiological correlates of classical conditioning in both Hermissenda and the rabbit, and the distribution of the enzyme within the rabbit hippocampus changes after Pavlovian conditioning [1].
• Here we report the identification of a 24 kDa phosphoprotein (CSP24) associated with an intermediate stage of memory, distinct from short-term memory, detected after one-trial conditioning of Hermissenda [2].

High impact information on Hermissenda

• Isolation of a G protein that is modified by learning and reduces potassium currents in Hermissenda [3].
• Light paired with serotonin mimics the effect of conditioning on phototactic behavior of Hermissenda [4].
• These results show that the ERK-MAPK signaling pathway is activated in Pavlovian conditioning of Hermissenda [5].
• Hermissenda received either light (conditioned stimulus or CS) and rotation (unconditioned stimulus or US) paired (i.e., Pavlovian conditioning), light and rotation unpaired (pseudoconditioning), or no exposure to light and rotation [6].
• Modulation of calcium current and diverse K+ currents in identified Hermissenda neurons by small cardioactive peptide B [7].

Chemical compound and disease context of Hermissenda

• In addition, electrophysiological and morphological studies indicate that 5-HT may contribute to cellular plasticity detected in the visual system of Hermissenda produced by classical conditioning procedures [8].

Biological context of Hermissenda

• Taken together, these results suggest that phototransduction in Hermissenda is mediated by Na+ channels that are directly activated by inositol trisphosphate without mobilization of cytosolic Ca2+ [9].
• In the nudibranch mollusk Hermissenda, phosphorylation and activation of the extracellular signal-regulated protein kinase (ERK), a key member of a MAPK cascade, is produced by one-trial and multitrial Pavlovian conditioning [10].
• Calcium waves and closure of potassium channels in response to GABA stimulation in Hermissenda type B photoreceptors [11].
• The effects of serotonin (5-HT) on membrane potential, membrane resistance, and select ionic currents were examined in large pedal neurons (LP1, LP3) of the mollusk Hermissenda [12].
• Accordingly, during Hermissenda conditioning a stronger dark adaptation is expected to render the CS (the light) more salient and hence facilitate association [13].

Anatomical context of Hermissenda

• The effects of serotonin (5-HT) and GABA on two Ca2+ currents, a transient low-voltage-activated current (tLVA) and a sustained high-voltage-activated current (sHVA) were examined in isolated photoreceptors of Hermissenda [14].
• Protein kinase C (PKC), an enzyme that plays an essential role in eukaryotic cell regulation (Nishizuka, 1988; Huang et al., 1989), is critical to memory storage processes both in the marine snail Hermissenda crassicornis and in the rabbit (Alkon et al., 1988; Bank et al., 1988; Olds et al., 1989) [1].
• We have found that two treatments, 4-aminopyridine and high external K+, which preferentially reduce the transient K+ current also reduce the level of 32P incorporation in a 25,000 molecular weight phosphoprotein band in eyes and ganglia of the nudibranch mollusc Hermissenda crassicornis [15].
• Previous observations have implicated GABA as a neurotransmitter released by the vestibular sensory neurons ("hair cells") of the snail Hermissenda onto visual sensory neurons, the type B cells, whose cell bodies are the sites of biophysical and biochemical changes during and following Pavlovian conditioning [16].
• These results indicate that GABA binding to G-protein-coupled receptors on Hermissenda B cells stimulates a PLA(2) signaling cascade that liberates AA, and that this free AA interacts with postsynaptic Ca(2+) to synergistically stimulate PKC and enhance neuronal excitability [17].

Associations of Hermissenda with chemical compounds

• GABA-mediated synaptic interaction between the visual and vestibular pathways of Hermissenda [18].
• The Hermissenda CNS C-kinase can also phosphorylate lysine-rich histone, a substrate for mammalian C-kinase [19].
• 1. N-type (omega-conotoxin sensitive) calcium currents (ICa) were recorded in identified neurons in Hermissenda crassicornis using low-resistance patch electrodes (0.7 +/- 0.3 M omega; n = 101) under conditions that eliminated inward Na+ currents (choline ions substitution) and suppressed outward K+ currents (Cs+, tetraethylammonium, and 4-AP) [20].
• In identified photoreceptors from the marine mollusc Hermissenda, recent evidence has suggested that GABA, as well as the GABAB receptor agonist baclofen, might simultaneously modulate multiple conductances on the postsynaptic membrane [21].
• Neither the biophysical or biochemical effects were observed in Hermissenda exposed to unpaired light and rotation or in those trained in the presence of the selective PKC inhibitor NPC-15437 (which had no effect on synaptic interactions or light-induced generator potentials) [22].

Gene context of Hermissenda

• Early reports indicated that both Hermissenda and squid CE also could bind GTP; however, the biochemical significance of GTP-binding and its relationship to calcium binding have remained unclear [23].
• Accordingly, we have investigated the catalytic properties of C-kinase in Hermissenda CNS [19].
• The 46- and 55-kDa phosphoproteins are putative structural proteins, and the 22-kDa phosphoprotein is proposed to be a protein kinase C substrate previously identified in Hermissenda following multitrial classical conditioning [24].
• PP1 inhibitors depolarize Hermissenda photoreceptors and reduce K+ currents [25].
• Similar exposure of homogenates of the Hermissenda nervous system to OAG and Ca2+ caused enhanced phosphorylation of specific proteins, indicating the presence of C-kinase in the Hermissenda nervous system [26].

References