| Id |
Subject |
Object |
Predicate |
Lexical cue |
| T1 |
88-341 |
DRI_Background |
denotes |
In response to hypoxia and other stress, the sympathetic (adrenergic) nervous system regulates arterial contractility and blood flow, partly through differential activities of the alpha1 (α1) - adrenergic receptor (AR) subtypes (α1A-, α1B-, and α1D-AR). |
| T2 |
342-559 |
DRI_Approach |
denotes |
Thus, we tested the hypothesis that with acclimatization to long-term hypoxia (LTH), contractility of middle cerebral arteries (MCA) is regulated by changes in expression and activation of the specific α1-AR subtypes. |
| T3 |
560-698 |
DRI_Approach |
denotes |
We conducted experiments in MCA from adult normoxic sheep maintained near sea level (300 m) and those exposed to LTH (110 days at 3801 m). |
| T4 |
699-844 |
DRI_Approach |
denotes |
Following acclimatization to LTH, ovine MCA showed a 20% reduction (n = 5; P<0.05) in the maximum tension achieved by 10-5 M phenylephrine (PHE). |
| T5 |
845-1029 |
DRI_Outcome |
denotes |
LTH-acclimatized cerebral arteries also demonstrated a statistically significant (P<0.05) inhibition of PHE-induced contractility in the presence of specific α1-AR subtype antagonists. |
| T6 |
1030-1177 |
DRI_Outcome |
denotes |
Importantly, compared to normoxic vessels, there was significantly greater (P<0.05) α1B-AR subtype mRNA and protein levels in LTH acclimatized MCA. |
| T7 |
1178-1359 |
DRI_Outcome |
denotes |
Also, our results demonstrate that extracellular regulated kinase 1 and 2 (ERK1/2)-mediated negative feedback regulation of PHE-induced contractility is modulated by α1B-AR subtype. |
| T8 |
1360-1454 |
DRI_Background |
denotes |
Overall, in ovine MCA, LTH produces profound effects on α1-AR subtype expression and function. |
