[Role of angiotensin-(1-7) in amino-acid-neurotransmitter-mediated blood pressure regulation in rat rostral ventrolateral medulla].
The present study was undertaken to investigate the linkage between angiotensin-(1-7) [Ang-(1-7)] and the release of amino acid neurotransmitters in the the rostral ventrolateral medulla (RVLM) by techniques of microinjection, microdialysis combined with high performance liquid chromatography (HPLC)-fluorescent detection. Unilateral microinjection of Ang-(1-7) into the RVLM of anesthetized rats produced an increase in mean arterial pressure (MAP) accompanied by an increased release of glutamate (Glu). In contrast, microinjection of Ang779, a selective antagonist of Ang-(1-7) receptor, caused a decrease in MAP with a decreased release of Glu and an increased release of glycine, taurine and gamma-aminobutyric acid. The pressor effect of Ang-(1-7) and the depressor effect of Ang779 were in part blocked by corresponding antagonists of amino acid receptors. These results suggest that the pressor effect of Ang-(1-7) in the RVLM may be partially due to an increased release of Glu, whereas the depressor effect of Ang779 may be partially attributed to a decreased release of Glu and an increased release of inhibitory amino acid neurotransmitters.
Wang
J
J
Department of Physiology, Medical College, Fudan University, Shanghai 200032.
Shen
L L
LL
Cao
Y X
YX
Sun
Z J
ZJ
Wang
Q
Q
Zhu
D N
DN
D000596:Amino Acids / Q000502:physiology*; D000803:Angiotensin I / Q000502:physiology*; D000818:Animals; D000959:Antihypertensive Agents; D001794:Blood Pressure / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism / Q000502:physiology*; D008845:Microinjections; D018377:Neurotransmitter Agents / Q000502:physiology*; D010446:Peptide Fragments / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D000596:Amino Acids; D000959:Antihypertensive Agents; D018377:Neurotransmitter Agents; D010446:Peptide Fragments; D000803:Angiotensin I; C118790:angiotensin I (1-7)