Table 1

Effects of nimodipine, ω-conotoxin GVIA, calmidazolium and KN-62 injected i.t. on ED₅₀ values for β-endorphin, morphine and DAMGO administered i.c.v. for the tail-flick inhibition

	ED₅₀^1-a
	β-Endorphin i.c.v.	Morphine i.c.v.	DAMGO i.c.v.
	nmol/mouse
i.t.
Control	0.19	1.10	0.0059
	(0.11–0.38)^1-b	(0.42–1.98)	(0.0028–0.0127)
Nimodipine (2.4 pmol)	0.75	1.14	0.0065
	(0.40–1.50)^1-c	(0.54–2.09)	(0.0030–0.0130)
ω-Conotoxin GVIA (0.33 pmol)	0.77	1.21	0.0070
	(0.39–1.48)^1-c	(0.57–2.54)	(0.0031–0.0143)
Calmidazolium (0.15 pmol)	0.82	1.18	0.0062
	(0.42–1.63)^1-c	(0.47–2.45)	(0.0027–0.0132)
KN-62 (0.14 pmol)	0.85	1.20	0.0058
	(0.43–1.72)^1-c	(0.50–2.51)	(0.0029–0.0131)

↵1-a ED₅₀ values were calculated according toLitchfield and Wilcoxon (1949).
↵1-b Numbers in parentheses indicate 95% confidence interval.
↵1-c Significantly different from control, P < .05.