Changes in rat striatum catecholamine during hypoxia with reference to protective effects of flunarizine.
We investigated the changes in dopamine, homovanillic acid, 3,4-dihydroxyphenylacetic acid, and norepinephrine content in striatum of rats ventilated with 5% oxygen in nitrogen gas. We also examined the effects of flunarizine, a calcium channel blocker, on these catecholamine levels. During 10-20 min. of hypoxia, the dopamine content gradually increased and the 3,4-dihydroxyphenylacetic acid and norepinephrine levels decreased, while the concentration of homovanillic acid remained unchanged. The concentrations of these substances subsequently returned to control values after 4 hr of room air breathing. In animals pretreated with intravenous flunarizine injection, there was a slight increase in dopamine, with no appreciable change in homovanillic acid or 3,4-dihydroxyphenylacetic acid content during 10-20 min. of hypoxia. The decrease in norepinephrine which occurred during 10-20 min. of hypoxia was identical between non-treated and flunarizine-treated animals. Catecholamine levels subsequently returned to control values after 4 hr of room air breathing. These results suggest that flunarizine minimizes the alterations in striatal catecholamine contents during hypoxic ventilation.
Yamazaki
M
M
Department of Anaesthesiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Masuda
T
T
Ito
Y
Y
Kuze
S
S
Momose
Y
Y
D000818:Animals; D001784:Blood Gas Analysis; D002395:Catecholamines / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D005444:Flunarizine / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D010100:Oxygen / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012997:Solvents; D015996:Survival Rate
D002395:Catecholamines; D012997:Solvents; D005444:Flunarizine; D010100:Oxygen