I had the same question myself, Squitz. I wrote the below response to another thread but it has equal application here. Still just one rule, Squitz ... no nicotine today, Never Take Another Puff! John

Animal studies suggest that different brain regions may re-sensitize or downregulate at different rates, some within a day but keep in mind that a rat's life expectancy is far shorter than a humans. This is the latest study -

Mugnaini M, Garzotti M, Sartori I, Pilla M, Repeto P, Heidbreder CA, Tessari M.


Excellent question, Sonya. I wish we had an single and consistent answer but science just isn't there yet. Everything I've read to date suggests that once nicotine's arrival stops resensitization commences in earnest and is completed rapidly in some brain regions, and with some types of acetylcholine receptors, while taking longer in others.

imageIn my mind, correctly or incorrectly, I like to relate the brain's capacity to "downregulate" receptor counts to other physical healing such as restoration of our sense of smell or the healing of cilia in bronchial tubes (our sweeper brooms). But even after the initial healing of those functions, I'm sure there's additional gradual ongoing sensitivity restoration over time. The probem is that research in this area is ongoing , new, studies are hard to compare, and most studies are of mice or rats, although we do a couple on humans.

New studies continue to come out and tend to openly declare how little we currently know in making statements such as "chronic nicotine exposure induces upregulation of nicotinic receptors, but the mechanisms underlying this phenomenon are not well understood" (see
Nuutinen S, Ekokoski E, Lahdensuo E, Tuominen RK. ). Downregulation has been studied even less.

Edited 1 time by FreedomNicotine Feb 15 09 8:47 AM.