We have investigated the existence of neural connections between the duodenum and the sphincter of Oddi (SO). Stimulation of duodenal myenteric fiber bundles elicited synaptic responses in SO neurons, which included nicotinic fast excitatory postsynaptic potentials (EPSPs), slow EPSPs, and α2-adrenoreceptor-mediated inhibitory postsynaptic potentials. After 48 h in organ culture, when extrinsic...

Patterned, spontaneous activity plays a critical role in the development of neuronal networks. A robust spontaneous activity is observed in vitro in spinal cord preparations isolated from immature rats. The rhythmic ventral root discharges rely mainly on the depolarizing/excitatory action of GABA and glycine early during development, whereas at later stages glutamate drive is primarily responsi...

Most neurons in the mammalian brain receive thousands of excitatory synaptic inputs that are widely distributed along the dendritic arbor and activated with varying degrees of synchrony. Summation of unitary synaptic excitatory postsynaptic potentials (EPSPs) at the dendrite is crucial for initiation of the action potential. Patterned neuronal activity, which is known to modify synaptic transmi...

Postsynaptic inhibition can operate by two distinct mechanisms: (1) membrane hyperpolarization and (2) shunting of excitatory postsynaptic currents. The arithmetic operations--either addition or multiplication--that synapses are able to perform during neuronal computations are determined by which of these two inhibitory mechanisms predominates. Hyperpolarizing IPSPs interact linearly with EPSPs...

We studied how a neuronal circuit composed of two neuron types connected by chemical and electrical synapses maintains constant its integrative capacities as neurons grow. For this we combined electrophysiological experiments with mathematical modeling in pairs of electrically-coupled Retzius neurons from postnatal to adult leeches. The electrically-coupled dendrites of both Retzius neurons rec...

Whereas ifenprodil has been used as a selective GluN1/GluN2B (NR1/NR2B, B-type) receptor antagonist to distinguish between GluN2B (NR2B) and GluN2A (NR2A)-containing N-methyl-d-aspartate receptors (NMDARs), TCN 201 (3-chloro-4-fluoro-N-[4-[[2-(phenylcarbonyl)hydrazino]carbonyl]benzyl]benzenesulphonamide) and TCN 213 [N-(cyclohexylmethyl)-2-[{5-[(phenylmethyl)amino]-1,3,4-thiadiazol-2-yl}thio]ac...

1. Repeated stimulation of the siphon skin results in short-term habituation of the reflex contractions of the gill (38). The habituation, in turn, is correlated with a depression of the excitatory postsynaptic potentials (EPSPs) in motor neurons from mechanoreceptor sensory neurons (SN) (7, 16). The present study was undertaken to examine the parametric features of the synaptic depression and ...

We conducted whole cell voltage-clamp and current-clamp recordings in slices of rat hypothalamus to test for local excitatory synaptic circuits. Local excitatory inputs to neurons of the paraventricular nucleus (PVN) and supraoptic nucleus (SON) were studied with the use of electrical and chemical stimulation. Extracellular electrical stimulation provided indirect evidence of local excitatory c...

Inputs from glutamatergic excitatory interneurons (EIN) to motor neurons in the lamprey spinal cord locomotor network exhibit activity-dependent depression during spike trains. The mechanism underlying this depression has been examined here, and its relevance to transmitter release during rhythmic activity has been investigated. The depression of EIN inputs was greater after larger initial EPSP...

The maturation of retinogeniculate excitatory transmission and intrathalamic inhibition was studied in slices of the dorsal LGN obtained from ferrets during the first 2 postnatal months. Response to optic tract stimulation at neonatal ages consisted of slow EPSPs lasting several hundred milliseconds. Application of the NMDA receptor antagonist D-(-)-2-amino-5-phosphonovaleric acid (D-APV) durin...