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Angiotensin II-generating system in dog and monkey ocular tissues
N Shiota1, Y Saegusa, K Nishimura
1Department of Pharmacology, Osaka Medical College, Takatsuki, Japan.
Clinical and Experimental Pharmacology & Physiology
|March 1, 1997
Summary
Chymase, an enzyme alongside angiotensin-converting enzyme (ACE), contributes to local angiotensin II generation in dog and monkey eyes. This study identifies chymase activity in ocular tissues, clarifying the intraocular system.
Area of Science:
- Ocular physiology
- Enzymology
- Cardiovascular research
Background:
- Angiotensin II (AngII) is produced locally in various tissues, including the eye.
- Chymase is a potential alternative enzyme for AngII generation, alongside angiotensin-converting enzyme (ACE).
- Previous studies suggest chymase presence in cardiovascular tissues.
Purpose of the Study:
- To investigate the contribution of chymase to AngII generation in dog and monkey ocular tissues.
- To elucidate the intraocular AngII-generating system.
- To determine if chymase is expressed in ocular tissues.
Main Methods:
- Measurement of chymase-like and ACE activities in ocular and cardiovascular tissues from dogs and monkeys.
- Quantification of chymase and ACE mRNA levels using competitive reverse transcriptase-polymerase chain reaction (RT-PCR).
Main Results:
- Chymase-like activity was found in the anterior uveal tract, choroid, and sclera of dog eyes.
- In monkey eyes, chymase-like activity was detected in the anterior uveal tract, exceeding levels in the heart.
- ACE activity was present in multiple ocular tissues in both species.
- Chymase and ACE mRNA were detected in tissues exhibiting enzymatic activity.
Conclusions:
- Chymase is expressed locally in dog and monkey ocular tissues, in addition to ACE.
- Chymase may play a role in the local generation of AngII within the eye.
- This study provides novel insights into the intraocular AngII-generating system.