Effects of pargyline on tele-methylhistamine and histamine in rat brain.
Rapid and complete inhibition of brain MAO produced linear increases in brain t-MH levels from 30 min to 4 hr after drug treatment at a rate of 0.26 nmole/g X hr, resulting in a 3-fold increase which persisted for at least 12 hr. HA levels were slightly elevated 1 and 2 hr after drug administration but quickly returned to control levels, suggestive of sensitive regulatory mechanisms in brain. Although the slight change in HA levels precludes steady-state assumptions, the rate of increase in brain t-MH levels after MAO inhibition provides a novel estimate of the half-life of endogenous brain HA (50 min). Despite the transient effect of pargyline on brain HA content, the effect of pargyline on brain t-MH levels suggests that MAO inhibitors may produce long-term alterations in brain histaminergic dynamics.
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D005260:Female; D006632:Histamine / Q000378:metabolism*; D008297:Male; D008761:Methylhistamines / Q000378:metabolism*; D010293:Pargyline / Q000494:pharmacology*; D010627:Phenethylamines / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D008761:Methylhistamines; D010627:Phenethylamines; D006632:Histamine; D010293:Pargyline; C020404:tele-methylhistamine