Relay neurons in sensory thalamus transmit somatosensory information to cerebral cortex and receive sensory and feedback corticothalamic (CT) synaptic inputs. Their duality of firing modes, in bursts and continuous, underlies state dependence of thalamic information transfer, but the impact of different firing patterns on synaptic plasticity was rarely explored. To address this issue, we made...

Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike...

Dı́az-Torga, Graciela, Arturo González Iglesias, Rita Achával-Zaia, Carlos Libertun, and Damasia BecúVillalobos. Angiotensin II-induced Ca21 mobilization and prolactin release in normal and hyperplastic pituitary cells. Am. J. Physiol. 274 (Endocrinol. Metab. 37): E534–E540, 1998.—We evaluated the effects of angiotensin II (ANG II) and its antagonists on prolactin release, intracellular calcium ...

Rhythmic oscillations of up to 600 Hz in grouped neurons frequently occur in the brains of animals. These high-frequency oscillations can be sustained in calcium-free conditions and may be blocked by gap junction blockers, implying a key role for electrical synapses in oscillation generation. Mathematical theories have been developed to demonstrate oscillations mediated by electrical synapses w...

Dendritic spikes that propagate toward the soma are well documented, but their physiological role remains uncertain. Our in vitro patch-clamp recordings and two-photon calcium imaging show that direction-selective retinal ganglion cells (DSGCs) utilize orthograde dendritic spikes during physiological activity. DSGCs signal the direction of image motion. Excitatory subthreshold postsynaptic pote...

The shape of action potentials plays an important role in synaptic integration. Action potentials of different shapes shunt excitatory potentials differentially and consequently correspond to different probabilities of generating the next spike. Thus two neurons producing different spikes shapes, say Purkinje and pyramidal cells, integrate differently the same excitatory potentials. More intere...

Cortical axons contain a diverse range of voltage-activated ion channels, including Ca(2+) currents. Interestingly, Ca(2+) channels are not only located at presynaptic terminals, but also in the axon initial segment (AIS), suggesting a potentially important role in the regulation of action potential generation and neuronal excitability. Here, using two-photon microscopy and whole-cell patch-cla...

Patch-clamp recordings were made from isolated and intact retinal ganglion cells (RGCs) of the ferret to examine the calcium-activated potassium channels expressed by these neurons and to determine their functional role in the generation of spikes and spiking patterns. Single-channel recordings from isolated neurons revealed the presence of two calcium-sensitive potassium channels that had cond...