Roles
The subunits of the nicotinic receptors belong to a multigene family (16 members in humans) and the assembly of combinations of subunits results in a large number of different receptors (for more information see the Ligand-Gated Ion Channel database). These receptors, with highly variable kinetic, electrophysiological and pharmacological properties, respond differently to nicotine, at very different effective concentrations. This functional diversity allows them to take part in two major types of neurotransmission. Classical synaptic transmission (wiring transmission) involves the release of high concentrations of neurotransmitter, acting on immediately neighboring receptors. In contrast, paracrine transmission (volume transmission) involves neurotransmitters released by synaptic buttons, which then diffuse through the extra-cellular medium until they reach their receptors, which may be distant. Nicotinic receptors can also be found in different synaptic locations; for example the muscle nicotinic receptor always functions post-synaptically. The neuronal forms of the receptor can be found both post-synaptically (involved in classical neurotransmission) and pre-synaptically where they can influence the release of multiple neurotransmitters.
Read more about this topic: Nicotinic Acetylcholine Receptor
Famous quotes containing the word roles:
“It was always the work that was the gyroscope in my life. I don’t know who could have lived with me. As an architect you’re absolutely devoured. A woman’s cast in a lot of roles and a man isn’t. I couldn’t be an architect and be a wife and mother.”
—Eleanore Kendall Pettersen (b. 1916)
“There is a striking dichotomy between the behavior of many women in their lives at work and in their lives as mothers. Many of the same women who are battling stereotypes on the job, who are up against unspoken assumptions about the roles of men and women, seem to accept—and in their acceptance seem to reinforce—these roles at home with both their sons and their daughters.”
—Ellen Lewis (20th century)
“A concern with parenting...must direct attention beyond behavior. This is because parenting is not simply a set of behaviors, but participation in an interpersonal, diffuse, affective relationship. Parenting is an eminently psychological role in a way that many other roles and activities are not.”
—Nancy Chodorow (20th century)