This hypoxia also causes the parasympathetic nerve fibers to die off.

这种缺氧还会导致副交感神经纤维死亡。

In both cases, the parasympathetic nerve fibers in the cavernosal spaces release acetylcholine from their nerve endings.

在这两种情况下，副交感神经纤维在海绵体间隙通过神经末梢释放乙酰胆碱。

Damaged parasympathetic nerve fibers can't release acetylcholine, so there's less nitric oxide synthase activation, and less nitric oxide is produced.

受损的副交感神经纤维不能释放乙酰胆碱，因此被激活的一氧化氮合酶较少，产生的一氧化氮也较少。