Figure 3: Effect of PACAP eye drops on tear secretion in male mice.
From: PACAP suppresses dry eye signs by stimulating tear secretion
(a) Representative images of the cotton thread measurements 30 min after administration of 10−10 M PACAP38 or saline eye drops with a 30 s insertion of the thread into both lower eyelids. The blue bar in the lower pictures shows the length of the tear-absorbed thread that changed colour from yellow to red. Scale bar, 10 mm. (b) Dose-response effect of PACAP38 eye drops on tear secretion in mice. Test solution eye drops were applied to both eyes. The sum of the wet length of cotton from the two eyes is shown on the Y-axis (n=10 per group). *P<0.05, **P<0.01. (c,d) Effect of PACAP27 (c) and VIP (d) eye drops on tear secretion (n=9–10 per group). **P<0.01 versus the saline-treated group. (e,f) Effect of 10−10 M PACAP38 eye drops on two lacrimal gland-deficient models: removal of the exorbital lacrimal gland (e) and removal of both the infraorbital and exorbital lacrimal glands (f) (n=10 per group). **P<0.01 versus the saline-treated group. (g,h) Effect of PAC1-R and VPAC2-R antagonist, PACAP6–38 (g) and VPAC1-R and VPAC2-R antagonist, VIP6–28 (h) treatments on PACAP-induced tear secretion (n=10 per group). *P<0.05, **P<0.01.
