Table 5. Remnant vasoconstriction after preincubation with phentolamine (0.1 μmol/L) on the frequency—contraction curves performed in mesenteric segments of control and pregnant rats.

	1 Hz	2 Hz	4 Hz	8 Hz
Control	24.1±3.23	41.06±2.84	59.14±2.22	77.76±3.90
Phentolamine Remnant	0.40±0.19*	2.17±0.88*	7.98±1.38*	18.35±5.54*
Pregnant	17.53±3.71	27.17±5.84	40.14±5.42	54.03±5.96
Phentolamine Remnant	0.61±0.4*	1.63±0.56*	3.72±2.06* #	9.97±3.63* #

Results (means ± S.E.M.) are expressed as percentages of the response elicited by 75 mM KCl.

*P<0.05 vs. conditions without phentolamine at each frequency (Bonferroni test).

^#P<0.05 vs. Control.

n = 8 animals per group.