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.
Glutamate. Glutamate is the most abundant excitatory neurotransmitter in the brain and spinal cord. It is released, for example, by afferent neurons. In many cases, the receptor is a ligand gated ion channel that produces fast postsynaptic potentials.cetylcholine. Acetylcholine is the neurotransmitter released by two types of neurons you hear about frequently in physiology: parasympathetic postganglionic neurons and somatic efferent neurons. In the parasympathetic case, the receptor is a seven transmembrane domain receptor coupled to a trimeric G protein.