Role of low-voltage-activated calcium current on the firing pattern alterations induced by hypothyroidism in the rat hippocampus.

Thyroid hormone deficiency during a critical period of development severely affects cognitive functions, resulting in profound mental retardation. Despite the importance of the disorder, the cellular mechanisms underlying these deficits remain largely unexplored. The aim of this study was to examine the effects of the absence of thyroid hormone on the development of the intrinsic properties of CA1 hippocampal pyramidal cells.

Augmentation of excitability in the hippocampus of juvenile rat.

The short-term plasticity of synaptic transmission has usually been related to neurotransmitter release-dependent processes. In this work, we describe a calcium- and release-independent augmentation of the fiber volley (FVA) that appears during stimulation of the Wistar rat commissural/Schaffer collateral afferents at 10-Hz. Among the possible mechanisms involved in this phenomenon, an increment in sodium channel density or the facilitation of recovery from inactivation does not seem to be responsible for this effect since the depolarization rate of the somatic action potentials (APs) of CA3 pyramidal cells decreases during the 10-Hz stimulation.

[Sutureless thyroidectomy with local anesthesia plus conscious sedation. Two clinical cases].

Objective: We proposed a modification of thyroid surgery and have reported two operations carried out with sutureless surgery and local anesthesia. Our study setting was Unit 305 of the General Hospital of Mexico in Mexico City. With regard to study design, two patients are presented with sutureless thyroid surgery in what we believe is the first publication of its kind in Mexico and probably the first publication in the world that reports the combination of both sutureless technique and local anesthesia.

Characterization of release-independent short-term depression in the juvenile rat hippocampus.

Short-term depression strongly influences neuronal activity in cerebral circuits and contributes to low-pass temporal filtering of information. In this work, we show that synaptic depression evoked by stimulation of commissural-Schaffer collateral afferents at 10 Hz is associated with a reduction of the fibre volley. This depression of action potentials is also evident in the absence of extracellular Ca(2+), which underlies its release-independent nature.

Age-dependent alterations of long-term synaptic plasticity in thyroid-deficient rats.

Thyroid hormone deficiency during a critical period of development profoundly affects cognitive functions such as attention, learning, and memory, but the synaptic alterations underlying these deficits remain unexplored. The present study examines the effect of congenital hypothyroidism on long-term synaptic plasticity. This plasticity is believed to be essential for learning and memory and for activity-dependent regulation of synapse formation in the developing brain.