Fig 6. Tyrosine hydroxylase and Tryptophan Hydroxylase levels in nicotine treated and non-treated Sph-1 expressing flies.

A) animals expressing Sph-1 in their dopaminergic neurons exhibit a significant reduction in their TH levels at one day post-eclosion. In contrast, flies expressing Sph-1 only in their serotonergic neurons do not show a significant reduction in TH levels. B) Animals expressing Sph-1 in either the serotonergic or dopaminergic system exhibit a significant reduction in TPH expression levels, with a more pronounced effect in flies expressing Sph-1 in both systems (UAS-Sph-1/+, ddc-GAL4/ +). C) TH expression levels in 40-day-old flies, with the control condition depicted in black and chronic nicotine treatment shown in red. TH levels tend to increase modestly but not significantly in nicotine-treated flies when the serotonergic or dopaminergic system is affected. D) TPH expression levels in 40-day-old flies, with the control condition shown in black and chronic nicotine treatment depicted in red. TPH levels are not affected in nicotine-treated flies. Statistical significance was determined using two-way ANOVAs followed by a Tukey post-hoc test, *p>0.05, **p>0.02, ***p>0.001, ****p>0.0001, ns = not significant, n = 3 independent samples. In all cases experimental animals were treated with 24 μM nicotine, full blots used for quantifications are shown in S1 and S2 Raw images.