[Central hypotensive effect involving neurotransmitters of long-term administration of taurine to stroke-prone spontaneously hypertensive rat].
BACKGROUND
Taurine is an inhibitory neurotransmitter or neuromodulator that reduces blood pressure when systemically or centrally administered. We studied the central hypotensive effects of long-term oral taurine administration.


METHODS
Arterial blood pressure was measured after delivering an intracisternal injection of 100 mg x 20 microl(-1) or 200 microg x 20microl(-1) of taurine in normal saline, or 20 micro1 normal saline to anesthetized Sprague-Dawley rats. Drinking water containing 3% taurine was administered to stroke-prone spontaneously hypertensive rats (SHRSP) from the age of 4 weeks. Amino acids and monoamine neurotransmitters in the cerebrospinal fluid were measured at 8, 12, 16, 18 weeks of age in taurine treated SHRSP and normotensive Wistar Kyoto rats (WKY) and in untreated SHRSP using high performance liquid chromatography.


RESULTS
Intracisternal injections of taurine caused a dose dependent decrease in arterial blood pressure. Although concentrations of taurine decreased in treated SHRSP rats in an age-related manner, the drug persistently suppressed the development of hypertension. The values of excitatory amino acids and GABA, norepinephrine, NMN, dopamine metabolites, serotonin and its metabolite were lower in taurine-treated SHRSP than those in untreated SHRSP.


CONCLUSIONS
Taurine reduces blood pressure through not only direct inhibition of the cardiovascular center in the medulla, but also by reducing brain monoamine concentrations.
Yoshioka
Megumi
M
Department of Anesthesiology, Kinki University School of Medicine, Osakasayama 589-8511.
Takasugi
Yoshihiro
Y
Koga
Yoshihisa
Y
D000284:Administration, Oral; D000375:Aging / Q000134:cerebrospinal fluid; D000818:Animals; D015306:Biogenic Monoamines / Q000134:cerebrospinal fluid*; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018846:Excitatory Amino Acids / Q000134:cerebrospinal fluid*; D007276:Injections, Intraventricular; D008297:Male; D018377:Neurotransmitter Agents / Q000134:cerebrospinal fluid*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D013654:Taurine / Q000008:administration & dosage* / Q000494:pharmacology*
D015306:Biogenic Monoamines; D018846:Excitatory Amino Acids; D018377:Neurotransmitter Agents; D013654:Taurine