Table 1.

Effect of α2 agonist (clonidine), α1 antagonist (prazosin), and β antagonist (propranolol) on CRF-induced changes in startle magnitude and % PPI (Mean ± SEM)

Startle Intensity (dB)	80		90		100		110		120
	Vehicle	oCRF	Vehicle	oCRF	Vehicle	oCRF	Vehicle	oCRF	Vehicle	oCRF
Vehicle	13 ± 2	28 ± 5	21 ± 4	46 ± 11	65 ± 9	105 ± 17	118 ± 21	274 ± 45	121 ± 24	413 ± 92*
Clonidine	8 ± 1	18 ± 4	13 ± 2	39 ± 7	39 ± 6	83 ± 21	79 ± 9	136 ± 23	108 ± 16	195 ± 23
Vehicle	14 ± 1	44 ± 12+	30 ± 6	70 ± 17	68 ± 12	89 ± 26	106 ± 17	202 ± 27	130 ± 23	375 ± 57*
Prazosin	18 ± 4	22 ± 3	31 ± 9	32 ± 10	67 ± 17	60 ± 11	106 ± 23	188 ± 40	124 ± 22	194 ± 50
Vehicle	13 ± 3	41 ± 12	26 ± 7	82 ± 22#	57 ± 6	111 ± 28	78 ± 13	153 ± 27	95 ± 13	246 ± 34#
Propranolol	12 ± 2	63 ± 3	20 ± 4	81 ± 16	49 ± 7	134 ± 25	80 ± 17	218 ± 34	87 ± 12	224 ± 32

Prepulse Intensity (dB)	68		71		77
	Vehicle	oCRFa	Vehicle	oCRFa	Vehicle	oCRF
Vehicle	35 ± 6	16 ± 4	47 ± 6	29 ± 4	61 ± 5	53 ± 4
Clonidine	33 ± 6	25 ± 2	53 ± 6	26 ± 5	66 ± 4	49 ± 6
Vehicle	24 ± 4	0.5 ± 13	39 ± 6	24 ± 9	58 ± 4	55 ± 7
Prazosin	14 ± 5	14 ± 5	36 ± 6	27 ± 7	53 ± 4	54 ± 8
Vehicle	36 ± 7	11 ± 12	54 ± 6	26 ± 11	68 ± 5	62 ± 7
Propranolol	26 ± 6	18 ± 5	48 ± 6	28 ± 7	54 ± 10	64 ± 4

^*p < 0.05, vs. all other groups at 120 dB

⁺p < 0.05, vs. all other groups at 80 dB

^#p <0.05, vs. Veh/Veh group only at 90 and 120 dB

^aSignificant main effect of oCRF on PPI at 68 and 71 dB prepulse trials in the propranolol experiment (see text for details)

Note: In the clonidine experiment, there was a significant main effect of oCRF on PPI at all prepulse intensities (see text for details).