STAMBP and Keratoconjunctivitis sicca: Importantly, both H89 and PD98059 abrogated the α-MSH’s improvements on clinical signs in the dry eye rats (Fig. 3, D+α-MSH vs D+H89+α-MSH, D+α-MSH vs D+PD+α-MSH, all p < 0.001), whereas the vehicle control, Dimethyl Sulfoxide (DMSO) did not (Fig. 3, D+α-MSH vs D+DMSO+α-MSH, p = 0.311 for Schirmer’s test, p = 0.249 for BUT, p = 0.414 for fluorescein staining).