Effects of electrical noise to a knee joint on quiet bipedal stance and treadmill walking.

The present study assessed whether an unperceivable, noise-like electrical stimulation of a knee joint enhances the stability of quiet bipedal stance and treadmill walking in young subjects. The results showed that the slow postural sway measures in quiet bipedal stance were significantly reduced by the electrical noise (P<0.05). In the treadmill walking, low frequency component (below 1 Hz) of mediolateral acceleration, measured at the third lumbar vertebra, significantly decreased with the electrical noise (P<0.05), while there were no changes in the anteroposterior and vertical directions. These results indicate that the electrical noise to a knee joint can be applied to enhance postural control in quiet bipedal stance and treadmill walking.

PACAP stimulates the release of interleukin-6 in cultured rat Müller cells.

We have investigated the in vivo effect of PACAP on rat Müller cells that are the predominant glial element in the retina. Müller cells were treated with PACAP38, either alone or in the presence of the PACAP-selective antagonist, PACAP6-38. Cellular proliferation was determined by measuring the incorporation of bromodeoxyuridine, while interleukin-6 (IL-6) levels in the culture medium were examined using a B9 cell bioassay. In cultured rat Müller cells, the expression of PACAP receptor (PAC1-R) was assessed with immunohistochemistry using a PAC1-R-specific antiserum. PACAP stimulated IL-6 production in Müller cells at a concentration as low as 10(-12) M, which was not sufficient to induce cell proliferation. This elevation of IL-6 production was significantly inhibited by PACAP6-38. These data suggest that Müller cells are one of the target cells for PACAP, stimulating the release of IL-6, and providing a mechanism whereby PACAP exerts a significant neuroprotective effect in the retina.