Tryptophan hydroxylase activity in rat brain base arteries related to innervation originating from the dorsal raphe nucleus.
OBJECTIVE
Tryptophan hydroxylase activity was assayed in cell-free extracts of rat brain base arteries as marker of a serotonergic innervation.


METHODS
Estimation of the enzymatic activity was made in untreated male Sprague-Dawley rats (n = 53) and in those who underwent destruction of the dorsal and median raphe nuclei (n = 10).


RESULTS
Tryptophan hydroxylase activity was measured in rat cerebral arteries. The time-dependent 5-hydroxytryptophan production was undetectable in the absence of tryptophan or 6-methyltetrahydropterine and in the presence of 6-fluorotryptophan, and it was significantly reduced in the presence of p-chlorophenylalanine. Destruction of the dorsal raphe nucleus but not the median raphe nucleus brought about a significant reduction in enzyme activity.


CONCLUSIONS
These results suggest that rat cerebral arteries receive a serotonergic innervation arising from the dorsal raphe nucleus.
Moreno
M J
MJ
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
López de Pablo
A L
AL
Marco
E J
EJ
D000818:Animals; D001921:Brain / Q000098:blood supply* / Q000201:enzymology; D002536:Cerebral Arteries / Q000201:enzymology* / Q000294:innervation; D008297:Male; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D009435:Synaptic Transmission; D014365:Tryptophan Hydroxylase / Q000378:metabolism*
D012701:Serotonin; D014365:Tryptophan Hydroxylase