Table 2.

Gating change of the 130 pS channel after chronic morphine

	Cells tested	Long bursts* (%)	Brief openings† (%)
Osmotic minipump
Vehicle, 6 days	15	5 (33)	0 (0)
Morphine, 2 mg/kg/h, 20 h	19	6 (32)	0 (0)
Morphine, 0.6 mg/kg/h, 6 days	21	3 (14)	4 (19)
Morphine, 2 mg/kg/h, 6 days	30	0 (0)	8 (27)‡
Morphine incubation in vitro
10 μM morphine, 6–8 h	38	13 (34)	0 (0)

^*Open probability: P₀ > 0.8 

^† P₀ < 0.06. 

^‡ P < 0.001 vs. vehicle or 20-h morphine.