Previous studies have shown that one form of neuroplasticity, population spike (PS) potentiation, can be established in the hamster hippocampus at temperatures above 20 degrees C. Here, we tested three related hypotheses; namely, that in Syrian hamsters: (1) PS potentiation can be elicited below 20 degrees C and that at any constant temperature, potentiation can be described by a pair of sigmoi...

In the present study, possible mechanisms involved in the tetanus-induced potentiation of gamma-aminobutyric acid-A (GABA-A) receptor-mediated inhibitory postsynaptic currents (IPSCs) were investigated using the whole cell voltage-clamp technique on CA1 neurons in rat hippocampal slices. Stimulations (100 Hz) of the stratum radiatum, while voltage-clamping the membrane potential of neurons, ind...

I have previously reported that norepinephrine (NE) induces a sustained potentiation of transmitter release in the chick ciliary ganglion through a mechanism pharmacologically distinct from any known adrenergic receptors. Here I report that the adrenergic potentiation of transmitter release was enhanced by a phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX) and by zaprinast, an in...

Long-term potentiation of hippocampal excitatory synapses is often accompanied by an increase in the probability of spiking to an EPSP of fixed strength (E-S potentiation). We used computer simulations of a CA1 pyramidal neuron to test the plausibility of the hypothesis that E-S potentiation is caused by changes in dendritic excitability. These changes were simulated by adding "hot spots" of no...

OBJECTIVE To investigate whether the human cerebellum takes part in fear conditioned potentiation of the acoustic blink reflex. METHODS A group of 10 cerebellar patients (eight patients with lesions involving the medial cerebellum, two patients with circumscribed lesions of the cerebellar hemispheres) was compared with a group of 16 age and sex matched healthy control subjects. The fear condi...

Dopaminergic neurotransmission modulates and influences hippocampal CA1 synaptic plasticity, learning and long-term memory mechanisms. Investigating the mechanisms involved in the slow-onset potentiation induced by the dopamine D1/D5 receptor agonists in hippocampal CA1 region, we have reported recently that it could play a role in regulating synaptic cooperation and competition. We have also s...

Diacylglycerol (DAG) and phorbol esters strongly potentiate transmitter release at synapses by activating protein kinase C (PKC) and members of the Munc13 family of presynaptic vesicle priming proteins. This PKC/Munc13 pathway has emerged as a crucial regulator of release probability during various forms of activity-dependent enhancement of release. Here, we investigated the relative roles of P...

In isolated hippocampal slices, decaying long-term potentiation can be stabilized and converted to late long-term potentiation lasting many hours, by prior or subsequent strong high-frequency tetanization of an independent input to a common population of neurons-a phenomenon known as 'synaptic tagging and capture'. Here we show that the same phenomenon occurs in the intact rat. Late long-term p...

The addition of an extra stimulus pulse, or doublet, at the beginning of a low-frequency train has been shown to substantially increase isometric force. This study examined the effects of muscle movement on this doublet potentiation. The soleus muscles of anesthetized cats were stimulated at 10 Hz for 1 s, with and without an added doublet (0.01-s interval). Isovelocity releases reduced but did...

Previous studies have shown that homosynaptic potentiation produced by rather mild tetanic stimulation (20 Hz, 2 sec) at Aplysia sensory-motor neuron synapses in isolated cell culture involves both presynaptic and postsynaptic Ca2+ (Bao et al., 1997). We have now investigated the sources of Ca2+ and some of its downstream targets. Although the potentiation lasts >30 min, it does not require Ca2...