Enhanced expression of Gi proteins in non-hypertrophic hearts from rats with hypertension-induced by L-NAME treatment
Bibliographic record
Abstract
OBJECTIVE: The objective of the present studies is to investigate if the enhanced expression of Gs alpha protein and their mRNA observed in various models of hypertensive rats is due to the expressed hypertrophy or hypertension. METHODS: Hypertension, in Sprague-Dawley rats was induced by the oral administration of the arginine analog N(omega)-nitro-L-arginine methyl ester (L-NAME) in their drinking tap water for a period of 4 weeks. The control rats were given plain tap water only. The levels of inhibitory guanine nucleotide regulatory proteins (Gi alpha-2, Gi alpha-3), stimulatory guanine nucleotide proteins (Gs alpha) and G beta proteins were determined by immunoblotting, whereas the levels of Gi alpha-2, Gi alpha-3, Gs alpha and adenylyl cyclase type V enzyme mRNA were determined by Northern-blotting techniques. Adenylyl cyclase activity was determined by measuring [32P]cAMP formation from [alpha32P]ATP. RESULTS: The systolic blood pressure was enhanced in L-NAME-treated rats compared to control rats (190 +/- 9.2 mmHg versus 121 +/- 6.3 mmHg); however, heart-to-body-weight ratio was not different in two groups. The levels of Gi alpha-2 and Gi alpha-3 proteins and their mRNA were significantly augmented in hearts from L-NAME-treated rats, however, the levels of Gs alpha and G beta were unaltered. In addition, the effect of low concentrations of GTPgammaS on forskolin (FSK)-stimulated adenylyl cyclase activity (receptor-independent functions of Gi alpha) was significantly enhanced in L-NAME-treated rats. However, the inhibitions of adenylyl cyclase exerted by oxotremorine, C-ANP(4-23) and angiotensin II (AII) (receptor-dependent function of Gi alpha) were completely attenuated in L-NAME-treated rats. On the other hand, cholera toxin stimulated GTP or GTPgammaS-sensitive adenylyl cyclase activity (Gs alpha function) to similar extent in control and L-NAME-treated rats, suggesting that Gs alpha functions were not altered by L-NAME treatment. However, the stimulatory effects of isoproterenol, glucagon, NaF on adenylyl cyclase were diminished in L-NAME-treated rats. In addition, FSK-stimulated enzyme activity was also diminished in L-NAME-treated rats without any changes in the mRNA levels of type V enzyme. CONCLUSIONS: These results suggest that L-NAME hypertensive rats that do not express cardiac hypertrophy exhibit enhanced expression of Gi alpha protein and associated adenylyl cyclase activity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".