the catheters were flushed daily with saline 0.4 cc, 0.2 cc saline containing heparin (70 u/cm3), and 0.1 cc of antibiotic ticarcillin (Timentin®, 100 mg/ cm3; GlaxoSmithKline, Research Triangle Park, NC). The implanted catheters were monitored daily for patency and those suspected of failure (self-administration BP decreased to <50%) were tested according to Mark et al. (2006), with a fast-acting barbiturate Brevital® (methohexital sodium; 2.7 mg/kg in 0.1 ml; Lilly, Indianapolis, IN). Catheters were considered to have failed if animals showed no substantial loss of muscle tone within 5 sec of Brevital® administration.
