A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
Acetylcholine. Acetylcholine (ACh) is the transmitter released by the preganglionic nerve terminals of both the sympathetic and the parasympathetic divisions (Fig 6.2). The synapse at those sites utilizes a nicotinic receptor similar in structure to the receptor at the neuromuscular junction.
In target cells, activates the production of cGMP. NO is the major inhibitory neurotransmitter causing relaxation of smooth muscle in the GI tract, and it is a significant contributor to the relaxation of vascular smooth muscle (Ach causes release of NO in the vasculature).