Calcium signaling pathways utilized by P2X receptors in freshly isolated preglomerular MVSMC.

This study tested the hypothesis that P2X receptor activation increases intracellular Ca(2+) concentration ([Ca(2+)](i)) in preglomerular microvascular smooth muscle cells (MVSMC) by evoking voltage-dependent calcium influx. MVSMC were obtained and loaded with the calcium-sensitive dye fura 2 and studied by using single-cell fluorescence microscopy. The effect of P2X receptor activation on [Ca(2+)](i) was assessed by using the P2X receptor-selective agonist alpha,beta-methylene-ATP and was compared with responses elicited by the endogenous P2 receptor agonist ATP. alpha,beta-Methylene-ATP increased [Ca(2+)](i) dose dependently. Peak increases in [Ca(2+)](i) averaged 37 +/- 11, 73 +/- 15, and 103 +/- 21 nM at agonist concentrations of 0.1, 1, and 10 microM, respectively. The average peak response elicited by 10 microM alpha,beta-methylene-ATP was approximately 34% of the response obtained with 10 microM ATP. alpha,beta-Methylene-ATP induced a transient increase in [Ca(2+)](i) before [Ca(2+)](i) returned to baseline, whereas ATP induced a biphasic response including a peak response followed by a sustained plateau. In Ca(2+)-free medium, ATP induced a sharp transient increase in [Ca(2+)](i), whereas the response to alpha,beta-methylene-ATP was abolished. Ca(2+) channel blockade with 10 microM diltiazem or nifedipine attenuated the response to alpha,beta-methylene-ATP, whereas nonspecific blockade of Ca(2+) influx pathways with 5 mM Ni(2+) abolished the response. Blockade of P2X receptors with the novel P2X receptor antagonist NF-279 completely but reversibly abolished the response to alpha,beta-methylene-ATP. These results indicate that P2X receptor activation by alpha,beta-methylene-ATP increases [Ca(2+)](i) in preglomerular MVSMC, in part, by stimulating voltage-dependent Ca(2+) influx through L-type Ca(2+) channels.

Cys-140 is critical for metabotropic glutamate receptor-1 dimerization.

Metabotropic glutamate receptor 1 (mGluR1) expresses at the cell surface as disulfide-linked dimers and can be reduced to monomers with sulfhydryl reagents. To identify the dimerization domain, we transiently expressed in HEK-293 cells a truncated version of mGluR1 (RhodC-R1) devoid of the extracellular domain (ECD). RhodC-R1 was a monomer in the absence or presence of the reducing agents, suggesting that dimerization occurs via the ECD. To identify cysteine residues involved in dimerization within the ECD, cysteine to serine point mutations were made at three cysteines within the amino-terminal half of the ECD. A mutation at positions Cys-67, Cys-109, and Cys-140 all resulted in significant amounts of monomers in the absence of reducing agents. The monomeric C67S and C109S mutants were not properly glycosylated, failed to reach the cell surface, and showed no glutamate response, indicating that these mutant receptors were improperly folded and/or processed and thus retained intracellularly. In contrast, the monomeric C140S mutant was properly glycosylated, processed, and expressed at the cell surface. Phosphoinositide hydrolysis assay showed that the glutamate response of the C140S mutant receptor was similar to the wild type receptor. Substitution of a cysteine for Ser-129, Lys-134, Asp-143, and Thr-146 on the C140S mutant background restored receptor dimerization. Taken together, the results suggest that Cys-140 contributes to intermolecular disulfide-linked dimerization of mGluR1.

Identification of the cysteine residues in the amino-terminal extracellular domain of the human Ca(2+) receptor critical for dimerization. Implications for function of monomeric Ca(2+) receptor.

We analyzed the effect of substituting serine for each of the 19 cysteine residues within the amino-terminal extracellular domain of the human Ca(2+) receptor on cell surface expression and receptor dimerization. C129S, C131S, C437S, C449S, and C482S were similar to wild type receptor; the other 14 cysteine to serine mutants were retained intracellularly. Four of these, C60S, C101S, C358S and C395S, were unable to dimerize. A C129S/C131S double mutant failed to dimerize but was unique in that the monomeric form expressed at the cell surface. Substitution of a cysteine for serine 132 within the C129S/C131S mutant restored receptor dimerization. Mutation of residues Cys-129, Cys-131, and Ser-132, singly and in various combinations caused a left shift in Ca(2+) response compared with wild type receptor. These results identify cysteines 129 and 131 as critical in formation of intermolecular disulfide bond(s) responsible for receptor dimerization. In a "venus flytrap" model of the receptor extracellular domain, Cys-129 and Cys-131 are located within a region protruding from one lobe of the flytrap. We suggest that this region represents a dimer interface for the receptor and that mutation of residues within the interface causes important changes in Ca(2+) response of the receptor.

Low energy laser therapy in rheumatoid arthritis.

Low energy laser (LEL) is a widely used treatment for a variety of musculoskeletal disorders although convincing documentation of the effect is missing. We have examined the LEL effect on Rheumatoid Arthritis (RA) in a double blind placebo controlled study. Twenty-two patients completed the study (10 receiving LEL treatment) according to the protocol. A significant effect on pain score was found due to LEL treatment, but when data were corrected for disease variation the effect disappeared. No effect of LEL could be demonstrated on the other assessed variables: grip strength, morning stiffness, flexibility, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). In conclusion, we did not find that LEL had any clinically relevant effects on RA.

Rebox: an adjunct in physical medicine?

Electrical therapy is used extensively in the treatment of musculoskeletal diseases. The best known form is transcutaneous electrical nerve stimulation (TENS). Rebox is another apparatus for electrical therapy that operates on much lower currents than TENS (0 to 300 microA). The effect of Rebox was tested on chronic lateral epicondylitis in 16 patients in a controlled crossover study. We found a significant effect of Rebox compared to placebo in respect to all the subjective and the objective variables: grip-strength, pain at power-grip and lifting a weightload with pronated forearm, and daily impairment.

[Possibilities of psychological intervention in patients following apoplectic stroke]. / Möglichkeiten psychologischer Interventionen bei Patienten nach apoplektischem Insult.

Mental training, progressive muscle relaxation, and client-centered psychotherapy are described as suitable methods of psychological treatment for stroke victims. It is important to direct the entire rehabilitation team toward better psychological guidance of patients. Key elements for success can be the use of a questionnaire to follow the progress of rehabilitation; the realization of a concept for continued professional training of the rehabilitation team; and the continuous exchange of information among the rehabilitation staff.