Expression and function of K(V)2-containing channels in human urinary bladder smooth muscle

The functional role of the voltage-gated K(+) (K(V)) channels in human detrusor smooth muscle (DSM) is largely unexplored. Here, we provide molecular, electrophysiological, and functional evidence for the expression of K(V)2.1, K(V)2.2, and the electrically silent K(V)9.3 subunits in human DSM. Stromatoxin-1 (ScTx1), a selective inhibitor of K(V)2.1, K(V)2.2, and K(V)4.2 homotetrameric channels and of K(V)2.1/9.3 heterotetrameric channels, was used to examine the role of these channels in human DSM function. Human DSM tissues were obtained during open bladder surgeries from patients without a history of overactive bladder. Freshly isolated human DSM cells were studied using RT-PCR, immunocytochemistry, live-cell Ca(2+) imaging, and the perforated whole cell patch-clamp technique. Isometric DSM tension recordings of human DSM isolated strips were conducted using tissue baths. RT-PCR experiments showed mRNA expression of K(V)2.1, K(V)2.2, and K(V)9.3 (but not K(V)4.2) channel subunits in human isolated DSM cells. K(V)2.1 and K(V)2.2 protein expression was confirmed by Western blot analysis and immunocytochemistry. Perforated whole cell patch-clamp experiments revealed that ScTx1 (100 nM) inhibited the amplitude of the voltage step-induced K(V) current in freshly isolated human DSM cells. ScTx1 (100 nM) significantly increased the intracellular Ca(2+) level in DSM cells. In human DSM isolated strips, ScTx1 (100 nM) increased the spontaneous phasic contraction amplitude and muscle force, and enhanced the amplitude of the electrical field stimulation-induced contractions within the range of 3.5-30 Hz stimulation frequencies. These findings reveal that ScTx1-sensitive K(V)2-containing channels are key regulators of human DSM excitability and contractility and may represent new targets for pharmacological or genetic intervention for bladder dysfunction.     

Lipid peroxidation changes in the brain in fetal alcohol syndrome]

The study was performed upon three groups of 12-week-old male rats. The first group of rats received ethanol/9 g/kg/day as 6% aqueous solution/during pregnancy and lactation, the second group received ethanol only during lactation and the third group, controls, received equicaloric sucrose solution. The concentrations of LPO products were determined in the homogenates of tissue from frontal cortex, striatum, hypothalamus, hippocamp and cerebellum. The concentration of fluorescent products in the brain structures of rats treated perinatally with ethanol was several-fold increased as compared with controls. The levels of diene conjugates were increased in most brain structures of rats with FAS. It should be pointed out that there was the same degree of increase of the levels of both fluorescent products and diene conjugates in two groups of rats with FAS. Having in mind that in the rat the increased growth of the brain occurs during the first 10 postnatal days, it might be assumed that this period is favorable for LPO.     

Quantification of the synapses in the hippocampus of aged rats

The synapses in the stratum lacunosum-molecular (str. L-M) of CA1 hippocampal field in 3-month old and 24-month old rats were examined using quantitative ultrastructural methods. No significant difference in the density of synapses and postsynaptic dendritic spines was found between the two age groups. The area of presynaptic terminals and postsynaptic dendritic spines was decreased slightly but significantly in the group of aged as compared to that in the group of young-mature rats. The vesicle number per presynaptic terminal, per area of presynaptic terminals and per volume of neuropil was not changed while the vesicle number per area of synaptic contact zones (SCZ) was increased in the group of aged rats. The mean length, total length and total surface of SCZ were diminished in the group of aged as compared to those in the group of young-mature rats. The same width of the str.radiatum and str.L-M in the two age groups showed that there was no any shrinkage of the neuropil in aged rats. The quantitative alterations in the synapses were accompanied by an increased number of dense and lamellar bodies in presynaptic terminals as well as with a presence of hypertrophic astroglial processes.     

Auditory Attention Activates Peripheral Visual Cortex

Background

Recent neuroimaging studies have revealed that putatively unimodal regions of visual cortex can be activated during auditory tasks in sighted as well as in blind subjects. However, the task determinants and functional significance of auditory occipital activations (AOAs) remains unclear.

Methodology/Principal Findings

We examined AOAs in an intermodal selective attention task to distinguish whether they were stimulus-bound or recruited by higher-level cognitive operations associated with auditory attention. Cortical surface mapping showed that auditory occipital activations were localized to retinotopic visual cortex subserving the far peripheral visual field. AOAs depended strictly on the sustained engagement of auditory attention and were enhanced in more difficult listening conditions. In contrast, unattended sounds produced no AOAs regardless of their intensity, spatial location, or frequency.

Conclusions/Significance

Auditory attention, but not passive exposure to sounds, routinely activated peripheral regions of visual cortex when subjects attended to sound sources outside the visual field. Functional connections between auditory cortex and visual cortex subserving the peripheral visual field appear to underlie the generation of AOAs, which may reflect the priming of visual regions to process soon-to-appear objects associated with unseen sound sources.     

Absorber Tower as a Photobioreactor for Microalgae

Green microalgae were grown under natural light in a photobioreactor similar to a transparent plate absorber. A proper temperature was maintained through the control of evaporation and the minimization of convective heat waste. Carbon dioxide desorption was lower in comparison to its level during cultivation in open or covered ponds. A yield of 1 g/l per day and over 100 g/m² projection area was achieved.