Table 1.

Results of 3-factor analysis of variance and Tukey post-hoc testing for heart rate of undisturbed SD and SHR rats and their heart rate responses to acute procedures

		Main effects			Interactions
Parameter	Procedure	light	strain	sex	light × strain	light × sex	strain × sex	light × strain × sex
Heart rate
	Undisturbed (morning)	L < C	SD > SHR	F > M	SHR: L < C	F: L < C
		D < C			D < C	D < C
		D = L			D = L	D = L
					SD: L = D = C	M: L < C
						D = C
						D = L
	Undisturbed (afternoon)	L < C	SD > SHR	F > M	SHR: L < C	F: L < C
		D < C			D < C	D < C
		D = L			D = L	D < L
						SD: L < C	M: L < C
						D < C	D < C
						D = L	L < D
	Undisturbed (night)	H	SD > SHR	F > M		F: L < C		H
						D < C
						L = D
						M: L < C
						D < C
						L < D
Heart rate responses
	Cage change	L = C	SD > SHR				SD: M > F
		D = C					SHR: M = F
		D > L
	Handling	H					H	H
	Insert cagemate	L = C	SD > SHR	M > F
		D < C
		D > L
	Remove cagemate	L = C	SD > SHR	F > M		F: L < C
		D < C				D < C
		D = L				D = L
						M: L = D = C
	SC injection	L < C	SD > SHR				SD: M > F
		D = C				SHR: M = F
		D > L
	Transport and SC injection	H	H	H		H	H	H
	Tail vein injection
	IP injection		SD > SHR
	Odors of male urine and feces	H	SD > SHR	F > M				H
	Odors of female urine  and feces	L < C	SD > SHR	F > M		F: L < C
		D = C				D < C
		D = L				D = L
					M: L = D = C
	Odor of dried blood		SD > SHR	F > M		F: L < C
						D = C
						D = L
						M: L = D = C
	60 min restraint	L > C	SD > SHR	M > F		F: L = D = C
		D = C				M: L > C
		D < L				D = C
						D < L

C, control (12:12-h light:dark photoperiod with 200 lx illumination); D, dim (10 lx) light; F, female; H, a significant light x strain x sex interaction prevented an unambiguous conclusion about indicated main effects and interactions; L, long nights (8:16-h light:dark photoperiod); M, male

Blank cells indicate nonsignificant effects.