Figure 4. Effect of bisindolylmaleimide, a specific PKC inhibitor, on 5-HT-stimulated CBF.

DMSO (0.01%, vehicle control) or bisindolylmaleimide (BIS; 10, 100 and 200 nM), added 10 min prior to determination of CBF, did not affect basal CBF. A characteristic increase in CBF in response to 5-HT (100 μM) was observed in cells pretreated with DMSO. Prior exposure to 10 and 100 nM bisindolylmaleimide significantly reduced 5-HT-induced ciliary activity. In contrast, 200 nM bisindolylmaleimide did not affect 5-HT-induced cilio-excitation. All pre-5-HT treatments are statistically similar (P > 0.05). Asterisks denote a statistically significant difference between pre- and post-addition of 5-HT (P < 0.05). Basal CBF values were: DMSO, 6.3 ± 0.8 beats s⁻¹ (n = 10 cells); bisindolylmaleimide (10 nM), 5.4 ± 0.3 beats s⁻¹ (n = 9 cells); bisindolylmaleimide (100 nM), 5.6 ± 0.4 beats s⁻¹ (n = 10 cells); bisindolylmaleimide (200 nM), 5.8 ± 0.2 beats s⁻¹ (n = 12 cells).