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Biotech / Medical : Gliatech (GLIA) -- Ignore unavailable to you. Want to Upgrade?

To: alexis s who wrote (893)	8/2/1999 11:02:00 PM
From: LLCF	Read Replies (1) \| Respond to of 2001

<so I wonder what happens to/in the brains of people who take anti-histamines?> Have you ever seen the Hammermill paper advertisements?? DAK

To: alexis s who wrote (893)	8/2/1999 11:46:00 PM
From: Biomaven	Read Replies (1) \| Respond to of 2001

alexis, so I wonder what happens to/in the brains of people who take anti-histamines? If they are taking first-generation antihistamines they get drowsy. There are at least 3 significantly different types of histamine receptors. H1 are those antihistamines work on; H2 those acid-blocking drugs like Zantac effect; and Glia is working on the more obscure H3. Peter

To: alexis s who wrote (893)	8/3/1999 12:21:00 AM
From: scaram(o)uche	Read Replies (1) \| Respond to of 2001

Alexis!! Good to hear from you. I'm real busy, but I should find time later tonight or tomorrow early. Not that I'm an expert.... maybe someone knowledgeable will come along and beat me to it. I see that Peter has given a part of the answer. Rick

To: alexis s who wrote (893)	8/6/1999 2:46:00 PM
From: scaram(o)uche	Respond to of 2001

Alexis: This certainly answers your question. However, it doesn't address the broader issues relating to what happens at H3 receptors, Remember, with respect to 2331, a receptor antagonist leads to increased release of histamine..... Nippon Yakurigaku Zasshi 1998 Oct;112 Suppl 1:48P-52P [Functional neuropharmacology in the human brain using positron emission tomography: PET imaging of impaired cognitive performance induced by sedative antihistamines]. [Article in Japanese] Yanai K, Okamura N, Itoh M, Watanabe T Department of Pharmacology I, Tohoku University School of Medicine, Sendai, Japan. Antihistamines are the efficacious drugs to be used for the symptomatic relief of allergic diseases. The safety issue of antihistamines is of central importance because of their widespread use in current medical practice. Positron emission tomography (PET) was used to better understand the pharmacological effects of antihistamines on the central nervous system. The H1 receptor occupancy was examined in young male volunteers with [11C]-doxepin after the oral or intravenous administration of antihistamines. In other studies, the cognitive performance was also measured tachistoscopically before and after taking antihistamines. The H1 receptor occupancy in the human cortex caused by antihistamines is significantly correlated with the reported values of incidence of sleepiness in clinical trials, and the occupancy is well proportional to the impaired cognitive performance. To understand the brain mechanism of antihistamine-induced "sleepiness and impaired cognition", the regional cerebral blood flow (rCBF) during the task was measured using 3D-PET and H2(15)O before and after administration of d-chlorpheniramine. After its administration, the rCBF was significantly decreased on the bilateral middle temporal gyrus, midbrain and anterior cingulate. These findings suggest that H1 receptor blockade would be affected on the activity of the attention and cognitive system in the brain.