The objectives of this study were to evaluate a technique for routine, noninvasive measurement of systemic arterial blood pressure and heart rate (HR) in conscious Beagle dogs for toxicologic research. HR, systolic, diastolic, and mean arterial (MAP) pressures were measured with a DINAMAP research monitor (Model 1255, Critikon, Inc.) as follows: Dogs were restrained in a Harvard dog sling, a neonatal cuff was wrapped around the base of the tail, and blood pressure and HR were determined once a minute. Initially, normal values were obtained, 5-10 trials/session, one to three sessions/day for 15 days in six dogs. The day to day, session to session, and trial variabilities were determined and found to be minimal. The day to day diastolic pressure ranged from 74 +/- 18 to 91 +/- 13 mm Hg, systolic pressure from 125 +/- 25 to 156 +/- 22 mm Hg, MAP from 94 +/- 20 to 113 +/- 15 mm Hg, and HR from 111 +/- 21 to 126 +/- 24 beats/minute (bpm). The effects of various drugs on these parameters were determined. Norepinephrine increased diastolic, systolic, and MAP by 75 to 110 mm Hg and decreased HR by half. Epinephrine increased HR by 20 bpm. Phentolamine decreased diastolic, systolic, and MAP by up to 25 mm Hg. Isoproterenol increased HR by up to 130 bpm and decreased diastolic, systolic, and MAP by 20 mm Hg. In addition, the effect of a classic drug interaction on these parameters was determined. When dogs pretreated with the monoamine oxidase inhibitor tranylcypromine were challenged with tyramine, diastolic, systolic, and MAP pressures were increased, whereas HR was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)