Fig 3. 6TM-mOR transfected Be2C cells show positive Ca²⁺ response to the stimulation with morphine.

(A) The percentage of Ca²⁺-responding cells upon 10 μM morphine treatment. Be2C cells transfected with 6TM-mOR, 7TM-mOR, or empty vector plasmids. *p<0.03, one-way ANOVA and Fisher’s LSD. Perfusion conditions: 1 min PBS; 59 min 10 μM morphine. (B) Time lapse images of Be2C cells transfected with 6TM-MOR at baseline (left; perfused with PBS) and after morphine treatment (right; perfused with 10 μM morphine). Ca²⁺ responses are imaged using Fura-2AM ratio-metric dye. Color scale shows the F340/380 fluorescence intensity ratio increase. Scale bar: 100 μm. (C) Ca²⁺ responses of individual 6TM-mOR-transfected cells, presented as increases in F340/380 fluorescence intensity; 10 μM morphine was perfused between 60–3600 s (blue bar).