Neuroprotective Activity of Fructose-1,6-Bisphosphate Following Transient Forebrain Ischemia in the Mongolian Gerbil

Abstract

ABSTRACT-In supine anesthetized rats, two cannulae were inserted into a unilateral ureter near the kidney and urinary bladder, respectively. Fluid from a reservoir placed approximately 27 cm above the rat was infused into the ureter lumen through the cannula near the kidney, and the resulting peristaltic pressure signals were measured from the cannula near the bladder. When drugs acting on ion channels were applied from the ureter lumen and their effects on the peristaltic pressure signals were studied, the K+ channel opener BRL 38227 (1 x 10-4 M and 1 x 10-3 M) was found to decrease the frequency dose-dependently. However, the K+ channel blockers glibenclamide and 4-aminopyridine at 1 X 10-3 M did not affect peristaltic movement. Nifedipine (1 x 10-5 M and 1 x 10-4 M) decreased the frequency of peristalsis, but the effect was weaker than that of BRL 38227. Lidocaine at very high concentration (1.5 x 10-2 and 1.5 x 10-' M) decreased the amplitude and increased the frequency of the peristaltic signals. These results indicate that the K+ channel opener has the most inhibitory effect on ureteral peristaltic function.

Inhibition of Human and Pig Ureter Motility in Vitro and in Vivo by the K+ Channel Openers PKF 217-744b and Nicorandil

“…Our findings regarding the inability of glibenclamide to antagonize the effects of K ϩ channel openers in the in vivo experiments were in accordance with the results of Kontani et al (1993a) who investigated the effects of glibenclamide on the ureter of anesthetized rats.…”

Effects of Levcromakalim on Ureteral Peristaltic Function and Cystometrogram in Rats

“…Another type of K+ channel that is blocked by 4-aminopyridine or tetraethylammo nium is reported (13). We did not investigate the effect of these drugs on ureteral peristaltic movement in the present experiment, since both drugs applied from the ure ter lumen at high concentration did not affect it (10).…”

“…Glibenclamide did not affect ureteral peristaltic movement when it was ap plied intravascularly or intraperitoneally in the present ex periment (Figs. 2 and 4) as well as from the ureter lumen in our previous report (10). We do not consider that the in jection route chosen may have caused glibenclamide to ex ert no effect on ureteral peristaltic movement, since nifedi pine inhibited ureteral peristaltic movement when it was intraperitoneally injected and applied from the ureter lu men (10).…”

“…For studying the effects of drugs on ureteral peristaltic movement, we used a method that was a partial modifi cation of our system previously used to investigate the effects of drugs applied from the ureter lumen (10). The experimental setup is shown in Fig.…”

“…Recently, we reported that lev cromakalim (BRL 38227), which is the (-)enantiomer of cromakalim and has identical properties but can be used at a lower dose level (9), had a strong inhibitory effect on myogenic ureteral peristaltic movement when a solution containing the drug was infused into the ureter lumen in anesthetized rats (10). The lower urinary tract, including the ureter, urinary bladder and urethral proximal sphinc ter, is composed of smooth muscle; and its function of urine transport, storage or evacuation (micturition) is dependent upon the integrated motility of these organs in the lower urinary tract.…”