(e:Paul),
(e:Terry) and I were discussing the relative merits of Claritin (Loratadine) in comparison with Benedryl (Diphenhydramine) in combating symptoms of allergy. Apart from remembering that Benedryl is a 1st generation antihistamine and that Loratadine is a 2nd generation antihistamine, I was sorry to note that I remembered nothing more about their pharmacology or specifics of how they differed from each other in their mechanism of action.
What follows is a dry account of the differences. Well... maybe not so dry because I am interested. :-)
Any allergic episode has two components: the early and late component. The early component is when the immunoglobulins (type E) recognize allergens, interact with the foot-soldier cells of the immune system. This interaction promotes the release of histamine, prostaglandins and leukotrienes from granules within not only mast cells, but also basophils, lymphocytes, and other reservoirs. Histamine then binds to receptors on nerves and blood vessels and leads to sneezing, tearing up, congestion and whatnots. Antihistamines compete with histamine for spots on the receptor and thus competitively reduce or completely block its action.
1st generation drugs such as diphenhydramine (Benedryl) also have additional anticholinergic, anti-serotonin, local anaesthetic, as well as sedative effects that might either provide a broader spectrum of relief from allergies or might just end up giving people more side effects (which explains the trippy experience I had.)
The late component of allergy is a plain inflammation reaction in the tissues mediated by immune cells called T-helper cells type-2 (Th2) and a host of cytokines (hormones/signalling molecules of the immune system). The inflammatory component feels exactly like a cold with the same reactions. In addition, the inflammatory component primes the immune response or "sensitizes" the immune system to even swifter allergy-induction in response to future allergens.
Loratadine (Claritin) not only binds to the histamine receptor, it also prevents the release of histamine as well as prostaglandins from mast cells - thus preventing "mast cell activation". Loratadine also has some effect on Th2 cells and suppresses some of the later inflammatory phase. It decreases the production of some of the late-phase cytokines. So it's not just an antihistamine. It also has none of the other wider receptor blocking effects of 1st gen antihistamines.
If you are inclined to read the nitty-gritties or how Loratadine acts on the immune system, here's a good review:
::READ PDF::
She is a trainer that specializes in motivational interviewing, she is doing the stretching as a side thing.
Unlimited summer yoga passes now to Aug. 31 $70!!! :::link::: I already got mine. I am committing myself to one yoga class each week during bar review. Wednesdays are most likely but there's one Tuesday nights that looks like it might be an okay alternative.
They have a PhD for physical trainers? Why am I not doing such a cool PhD programme?!
It was just me and someone else from my office with the PHD trainer they hired, it really did seem helpful to do that this morning. We did it in the short period of time when we get there and when the phone lines open. She is hoping to do this twice a week with a couple people each time.
Unfortunately, no :( I have too much on my mind... I don't think I can afford the 1.5 hour today. I am promising myself that I will go regularly from next week till the end of summer...
Speaking of stretching - are you going tonight?
That is funny, (e:libertad)! Was it for your office alone or for the whole institute?
Well.. stretching is exercise. The best form there is! :)
A couple of those stretches look a lot like a couple exercises....
That's funny you wrote this today. Today at the start of my work day we went outside and did stretches and simple yoga poses. They are testing allowing us to do this a couple of times a week. We shall see how long that lasts. It was a really nice surprise this morning.