Semisynthetic photoprotein reporters for tracking fast Ca(2+) transients.

Changes in the intracellular concentration of free ionized calcium ([Ca(2+)]i) control a host of cellular processes as varied as vision, muscle contraction, neuronal signal transmission, proliferation, apoptosis etc. The disturbance in Ca(2+)-signaling causes many severe diseases. To understand the mechanisms underlying the control by calcium and how disorder of this regulation relates to pathological conditions, it is necessary to measure [Ca(2+)]i.

Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues.

The main analytical use of Ca(2+)-regulated photoproteins from luminous coelenterates is for real-time non-invasive visualization of intracellular calcium concentration ([Ca(2+)]i) dynamics in cells and whole organisms. A limitation of this approach for in vivo deep tissue imaging is the fact that blue light emitted by the photoprotein is highly absorbed by tissue. Seven novel coelenterazine analogues were synthesized and their effects on the bioluminescent properties of recombinant obelin from Obelia longissima and aequorin from Aequorea victoria were evaluated.

Differences in the spinal command of ejaculation in rapid ejaculating rats.

Introduction: It has been hypothesized that lifelong premature ejaculation is part of a biological variation in the intravaginal ejaculation latency, but what causes this variation remains poorly understood.

Aim: The aim of this study is to elucidate whether variations in ejaculation latencies in an experimental rat model for premature ejaculation are linked to differences in the spinal command of ejaculation.

Main Outcome Measures: Electrical microstimulation of the spinal generator for ejaculation revealed an accelerated expulsion phase in rapid ejaculating rats.

Ejaculation elicited by microstimulation of lumbar spinothalamic neurons.

Background: Neuroanatomical and lesion studies have identified lumbar spinothalamic (LSt) neurons to be essential for ejaculation, but their precise role remains elusive.

Objective: To assess the role of LSt neurons as a spinal pattern generator for ejaculation (SGE) and their action on anatomical structures involved in the two ejaculation phases, the emission and expulsion of semen.

Design: The bulbospongiosus muscle (BSM) was implanted with electrodes and the seminal vesicle (SV) or vas deferens (VD) lumen catheterized in adult anaesthetized rats.

Facilitating sensory responses in developing mouse somatosensory barrel cortex.

The sensory responses in the barrel cortex of mice aged postnatal day (P)7-P12 evoked by a single whisker deflection are smaller in amplitude and spread over a smaller area than those measured in P13-P21 mice. However, repetitive 10-Hz stimulation or paired pulse whisker stimulation in P7-P12 mice evoked facilitating sensory responses, contrasting with the depressing sensory responses observed in P13-P21 mice. This facilitation occurred during an interval ranging 300-1,000 ms after the first stimulus and was measured using whole cell recordings, voltage-sensitive dye imaging, and calcium-sensitive dye imaging.

Differential and long-lasting alterations of high-voltage activated calcium currents in CA1 and dentate granule neurons after status epilepticus.

The effects on high-voltage activated (HVA) calcium currents were examined in hippocampal CA1 cells and dentate gyrus (DG) granule neurons, 2 days (short-term; ST) and 2-3 months (long-term; LT) after electrically induced, limbic electrographic and behavioural seizures in rats. Whole-cell voltage-clamp recordings in dissociated CA1 neurons of LT rats showed a decrease in the sustained HVA calcium current amplitude and a faster inactivation of the current both in rats that had experienced a status epilepticus (post-SE rats) and those in which the stimulation did not lead to SE (non-SE rats). In CA1 neurons of LT-SE rats this resulted in a reduced Ca2+ entry through the HVA channels.

Regulation of AMPA receptor lateral movements.

An essential feature in the modulation of the efficacy of synaptic transmission is rapid changes in the number of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors at post-synaptic sites on neurons. Regulation of receptor endo- and exocytosis has been shown to be involved in this process. Whether regulated lateral diffusion of receptors in the plasma membrane also participates in receptor exchange to and from post-synaptic sites remains unknown.