BL-1249 [(5,6,7,8-tetrahydro-naphthalen-1-yl)-[2-(1H-tetrazol-5-yl)-phenyl]-amine] produced a concentration-dependent membrane hyperpolarization of cultured human bladder myocytes, assessed as either a reduction in fluorescence of the voltage-sensitive dye bis-(1,2-dibutylbarbituric acid)trimethine oxonol (EC 50 ϭ 1.26 Ϯ 0.6 M) or by direct electrophysiological measurement (EC 50 ϭ 1.49 Ϯ 0.08 M). BL-1249 also produced a membrane hyperpolarization of acutely dissociated rat bladder myocytes. Voltage-clamp studies in human bladder cells revealed that BL-1249 activated an instantaneous, noninactivating current that reversed near E K . The BL-1249-evoked outward K ϩ current was insensitive to blockade by glyburide, tetraethylammonium, iberiotoxin, 4-aminopyridine, apamin, or Mg 2ϩ . However, the current was inhibited by extracellular Ba 2ϩ

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Twelve young bulls and 12 steers were slaughtered and the carcasses were fabricated at 48 h postmortem. Top rounds, bottom rounds, and rib eyes were vacuum-packaged and stored at 0 degrees C until 21 d postmortem. After subprimal storage, steaks were removed from each cut and displayed under simulated retail conditions for 3 d. Consumer panelists (n = 110) showed little difference in buying preference for top round, bottom round, and rib eye steaks from steers vs bullocks. Also, consumer panelists could not detect color differences between steaks from steers and bullocks. Experienced panelists (n = 6) detected brighter (P less than .05) muscle color for top round and rib eye steaks from steers but detected no difference in muscle color of bottom round steaks from bullocks and steers. Generally, overall desirability scores favored steaks from steer carcasses. This was particularly true of rib eye steaks. Sex-class of carcass did not affect aerobic plate counts of top round, bottom round, or rib eye steaks either before or after 3 d of retail display. Muscle pH was lower for top round and rib eye steaks from steer carcasses; however, the magnitude of this difference was not large enough to affect retail display stability. Muscle pH of bottom round steaks was not affected by sex-class. Although experienced panelists could detect differences in visual appearance of beef retail cuts from steers and bullocks, consumer panelists did not show a clear purchase preference for steer vs bullock beef. These data suggest that beef retail cuts from bullocks are acceptable in visual appearance.

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Forty-four Charolais crossbred bulls and steers from a similar background and fed commercially were slaughtered and the right side of each carcass was electrically stimulated. Electrical stimulation reduced lean maturity scores (bulls and steers) and, for steers, lowered lean firmness scores (softer lean) and improved "heat-ring" scores. Electrical stimulation significantly improved most tenderness measurements on steaks from young bulls, but was only effective in decreasing shear force values of steaks from steers. Electrical stimulation was more effective in improving the tenderness of steaks from bulls than those from steers. palatability of beef from bulls and steers from a similar genetic and management background. General MATERIALS & METHODSForty-four i/z-blood Charolais and 3/4-to 7/s-blood Charolais bulls and steers from the same herd were fed commercially (172 days) and slaughtered. Cattle were held by sex-breed group (n = 11) overnight with water and then transported to the plant on the morning of slaughter. Within 2 hr of arrival, the cattle were slaughtered.