Dennis L. Glanzman

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Noxious stimuli, such as electrical shocks to the animal's tail, enhance Aplysia's gill- and siphon-withdrawal reflex. Previous experimental work has indicated that this behavioral enhancement, known as dishabituation (if the reflex has been habituated) or sensitization (if it has not been habituated), might be mediated, at least in part, by the endogenous(More)
The mechanisms underlying structural changes that accompany learning and memory have been difficult to investigate in the intact nervous system. In order to make these changes more accessible for experimental analysis, dissociated cell culture and low-light-level video microscopy were used to examine Aplysia sensory neurons in the presence or absence of(More)
To determine the influence that an appropriate target cell has on the axonal structure of a presynaptic neuron in vivo, we examined the morphologies of individual Aplysia sensory neurons in dissociated cell culture in the presence or absence of identified target motor neurons. We find that an appropriate target, the motor cell L7, regulates the(More)
1. Serotonin (5-HT) facilitates the connections between sensory and motor neurons in Aplysia during behavioural sensitization. The effect of 5-HT on sensorimotor synapses is believed to be primarily presynaptic. Here we tested whether 5-HT can have an exclusively postsynaptic facilitatory effect. 2. Siphon motor neurons were individually dissociated from(More)
Recent studies have shown that, in addition to being modulated by presynaptic facilitation, the sensory neurons of the gill- and siphon-withdrawal reflex of Aplysia are also capable of being modulated by transient presynaptic inhibition produced by the peptide Phe-Met-Arg-Phe-NH2. These two modulatory effects involve different second-messenger systems: the(More)
Long-term potentiation (LTP) is considered an important neuronal mechanism of learning and memory. Currently, however, there is no direct experimental link between LTP of an identified synapse and learning. A cellular analog of classical conditioning in Aplysia was used to determine whether this form of invertebrate learning involves N-methyl-D-aspartate(More)
Long-term potentiation (LTP) of Aplysia sensorimotor synapses in cell culture can be induced by pairing sensory neuron activity with depolarization of the motorneuron. This pairing-induced LTP is prevented by perfusion with D,L-2-amino-5-phosphononovalerate (APV), a selective antagonist for the N-methyl-D-asparate (NMDA) subclass of glutamate receptors.(More)
We previously showed that the associative enhancement of Aplysia siphon sensorimotor synapses in a cellular analog of classical conditioning is disrupted by infusing the Ca(2+) chelator 1, 2-bis(2-aminophenoxy)ethane-N,N-N',N'-tetraacetic acid into the postsynaptic motor neuron before training or by training in the presence of the NMDA receptor antagonist(More)
The amygdaloid complex is functionally implicated in conditioned taste aversion (CTA) learning. Results of previous neurobehavioral studies have provided equivocal evidence concerning the involvement of specific amygdaloid nuclei in CTA learning. The present study was conducted to examine the involvement of the central (CE), lateral (LA), and basolateral(More)
Crushing nerves, which contain the axons of central sensory neurons, in Aplysia causes the neurons to become hyperexcitable and to sprout new processes. Previous experiments that examined the effects of axonal injury on Aplysia sensory neurons have been performed in the intact animal or in the semi-intact CNS of Aplysia. It therefore has been unclear to(More)