Effect of synthetic bag cell and atrial gland peptides on identified nerve cells in <i>Aplysia</i>

Rock, Michael K.; Shope, S.B.; Blankenship, James E.; Schlesinger, David H.

doi:10.1002/neu.480170403

Cited by 17 publications

(8 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, Wayne and Frumowitz (1995) showed that calcium influx is not required for release, provided that the discharge is started in the presence of normal external calcium. Both in bag cells and CDCs, initiation and maintenance of the discharge require the release of autoexcitatotory peptides (Rock et al, 1986;Brown and Mayeri, 1989;Brussaard et al, 1990;Loechner and Kaczmarek, 1994), which does require external calcium. Furthermore, firing may be ended by inhibitory autotransmission (Kauer et al, 1987;Redman and Berry, 1991).…”

Section: Hormone Releasementioning

confidence: 99%

Voltage gated calcium channels in molluscs: classification, Ca2+ dependent inactivation, modulation and functional roles

Kits

Mansvelder

1996

Invertebrate Neuroscience

View full text Add to dashboard Cite

Molluscan neurons and muscle cells express transient (T-type like) and sustained LVA calcium channels, as well as transient and sustained HVA channels. In addition weakly voltage sensitive calcium channels are observed. In a number of cases toxin or dihydropyridine sensitivity justifies classification of the HVA currents in L, N or P-type categories. In many cases, however, pharmacological characterization is still preliminary. Characterization of novel toxins from molluscivorous Conus snails may facilitate classification of molluscan calcium channels. Molluscan preparations have been very useful to study calcium dependent inactivation of calcium channels. Proposed mechanisms explain calcium dependent inactivation through direct interaction of Ca2+ with the channel, through dephosphorylation by calcium dependent phosphatases or through calcium dependent disruption of connections with the cytoskeleton. Transmitter modulation operating through various second messenger mediated pathways is well documented. In general, phosphorylation through PKA, cGMP dependent PK or PKC facilitates the calcium channels, while putative direct G-protein action inhibits the channels. Ca2+ and cGMP may inhibit the channels through activation of phosphodiesterases or phosphatases. Detailed evidence has been provided on the role of sustained LVA channels in pacemaking and the generation of firing patterns, and on the role of HVA channels in the dynamic changes in action potentials during spiking, the regulation of the release of transmitters and hormones, and the regulation of growth cone behavior and neurite outgrowth. The accessibility of molluscan preparations (e.g. the squid giant synapse for excitation release studies, Helisoma B5 neuron for neurite and synapse formation) and the large body of knowledge on electrophysiological properties and functional connections of identified molluscan neurons (e.g. sensory neurons, R15, egg laying hormone producing cells, etc.) creates valuable opportunities to increase the insight into the functional roles of calcium channels.

show abstract

Section: Hormone Releasementioning

confidence: 99%

Voltage gated calcium channels in molluscs: classification, Ca2+ dependent inactivation, modulation and functional roles

Kits

Mansvelder

1996

Invertebrate Neuroscience

View full text Add to dashboard Cite

show abstract

“…Neither (Y-BCP, y-BCP, ELH, nor ARG-VAS significantly affected the EPSP. The fact that o(-BCP produced no effect was interesting given that the majority of the inhibitory effects on neuronal activity in the abdominal ganglia produced by BCE or by activation of the bag cells have been ascribed to the action of o(-BCP (Rothman et al, 1983;Rock et al, 1986;Sigvardt et al, 1986). Likewise, the attenuation of sensory-to-motor neuron synapses in the abdominal ganglion produced by ARG-VAS (Goldberg et al, 1987) suggested that it might have similar actions in the pleural-pedal ganglia.…”

Section: Bce Suppresses Long-term Sensitizationmentioning

confidence: 99%

Bag cell extract inhibits tail-siphon withdrawal reflex, suppresses long-term but not short-term sensitization, and attenuates sensory-to- motor neuron synapses in Aplysia

Goldsmith

Byrne

1993

J. Neurosci.

View full text Add to dashboard Cite

The peptides released from the bag cells (bag cell peptides, BCPs) in Aplysia californica are responsible for eliciting or modulating a repertoire of behaviors preceding and accompanying egg laying. Our interest was in determining to what extent behaviors that can occur simultaneously with egg laying are modulated. To address this issue, we examined the effects of an extract (bag cell extract, BCE) that contained BCPs, as well as egg-laying hormone (ELH), an identified BCP, on both the tail-siphon withdrawal reflex and the ability of that reflex to exhibit sensitization, a simple form of nonassociative learning. In addition, we examined the ability of BCE, as well as the individual BCPs, to modulate a component of the circuitry of the reflex. Behavioral experiments indicated that BCE inhibited the baseline withdrawal reflex and suppressed long-term sensitization of the reflex while leaving short-term sensitization unaffected. These effects were not observed in animals receiving an extract of a control ganglion or in animals receiving ELH, and therefore may be attributed to the actions of one or more BCPs, but presumably not to ELH alone. Electrophysiological experiments revealed that BCE also attenuated the monosynaptic EPSP elicited in tail motor neurons by tail sensory neurons. In subsequent experiments in which the BCPs were individually applied, only one BCP, beta-BCP, significantly attenuated the EPSPs. This effect was independent of narrowing of the presynaptic action potential. Taken together, these results suggest a novel behavioral modification attributed to BCPs, inhibition of the tail-siphon withdrawal reflex, and suggest a possible locus of action and peptide candidate for this effect. In addition, these experiments raise the possibility that BCPs may exert a long-lasting effect (> 24 hr), selectively blocking a simple form of long-term memory.

show abstract

“…The typical thresholds for depolarizing responses were between lo-* and lo-' M for o(-BCP and P-BCP, and between lo-' and 10m6 M for T-BCP. Higher concentrations of a-BCP or /I-BCP can initiate regenerative burst discharges (see also Rothman et al, 1983;Rock et al, 1986).…”

Section: Autoexcitatory Effects Of Cy- P- and -Pbcpsmentioning

confidence: 99%

Positive feedback by autoexcitatory neuropeptides in neuroendocrine bag cells of Aplysia

Mayeri

1989

J. Neurosci.

View full text Add to dashboard Cite

Neurohormones are often secreted in large amounts from neuroendocrine cells during episodes of synchronous, repetitive spike activity. We report evidence that this pattern of activity in the neuroendocrine bag cells of Aplysia involves positive feedback by autoexcitatory transmitters. Intracellular stimulation of individual bag cells caused slow depolarizing afterpotentials and synchronous afterdischarges in the entire population of bag cells. Application of the bathing medium collected during bag cell activity mimicked these responses. Application of alpha-, beta-, or gamma-bag cell peptides (BCPs), 3 structurally related neuropeptides released from bag cells, also mimicked these responses. These autoexcitatory BCPs fulfill most of the strict criteria necessary for classification as neurotransmitters in this system. This is the first biological activity reported for beta- and gamma-BCPs and brings to 4 the number of bag cell neuropeptides derived from the egg-laying hormone/BCP precursor that are putative cotransmitters. Positive feedback by autoexcitatory transmission may provide a general mechanism for the generation of episodic activity in neuroendocrine systems.

show abstract

Effect of synthetic bag cell and atrial gland peptides on identified nerve cells in Aplysia

Cited by 17 publications

References 31 publications

Voltage gated calcium channels in molluscs: classification, Ca2+ dependent inactivation, modulation and functional roles

Voltage gated calcium channels in molluscs: classification, Ca2+ dependent inactivation, modulation and functional roles

Bag cell extract inhibits tail-siphon withdrawal reflex, suppresses long-term but not short-term sensitization, and attenuates sensory-to- motor neuron synapses in Aplysia

Positive feedback by autoexcitatory neuropeptides in neuroendocrine bag cells of Aplysia

Contact Info

Product

Resources

About