-transparent.png){kind=logo}
While the interactions between angiotensin II (Ang II) and norepinephrine (NE) on cardiovascular responses are well known, their effects on renin responses are not. We determined the renin secretion rate (RSR) and intracellular calcium level in juxtaglomerular cells harvested from Sprague-Dawley rats using a radioimmunoassay and a two-dimensional calcium analyzer. The effect of Ang II and NE was inhibitory on RSR and stimulatory on intracellular calcium. The NE-induced RSR response was amplified in the presence of Ang II (20 nmol/l). The NE-induced intracellular calcium response was also potentiated by the Ang II. There was a significant correlation (r = 0.994, p < 0.0001) between the changes in the RSR and those in intracellular calcium levels. Losartan (0.1 mumol/l). an Ang II type 1 receptor antagonist, blocked the Ang II threshold RSR responses and completely abolished the Ang II-related enhancements. The exclusion of calcium from the buffer reduced the maximal RSR response to NE but did not prevent the enhancement, suggesting the importance of the mobilization of intracellular calcium in the mechanism. The Ang II-induced RSR was amplified in the presence of NE (0.2 mumol/l). The Ang II-induced intracellular calcium response was also potentiated by the NE. A significant correlation (r = 0.996, p < 0.0001) between the changes in the RSR and the changes in intracellular calcium levels was also noted. Prazosin (1 mumol/l), an alpha 1-adrenoceptor antagonist, blocked the NE threshold RSR responses and abolished the agonist-related enhancements. The calcium-free buffer diminished this amplication with a slight decrease in the maximum RSR response to Ang II.(ABSTRACT TRUNCATED AT 250 WORDS)
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
August 1992,
American journal of hypertension,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
October 1974,
Japanese circulation journal,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
August 1982,
Kidney international. Supplement,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
September 1987,
Pflugers Archiv : European journal of physiology,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
June 1991,
Kidney international. Supplement,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
October 1971,
Revue europeenne d'etudes cliniques et biologiques. European journal of clinical and biological research,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
November 1984,
Kokyu to junkan. Respiration & circulation,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
July 1993,
The American journal of physiology,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
June 1981,
Proceedings of the National Academy of Sciences of the United States of America,
A Ichihara, and
H Suzuki, and
M Murakami, and
M Naitoh, and
A Matsumoto, and
T Saruta
May 1997,
Hypertension (Dallas, Tex. : 1979),
