Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries

Abstract

The present study aimed to evaluate the effects of chronic exercise on vasodilator response in two different arteries. Rings of carotid and femoral arteries from control and trained rabbits were suspended in organ baths for isometric recording of tension. Endothelial nitric oxide synthase (eNOS), Cu/Zn and Mn-superoxide dismutase (SOD), and large conductance calcium activated potassium (BKCa) channel protein expression were measured by western blotting. In the carotid artery, training reduced the relaxation to ACh (10 to 3 × 10 m) that was reversed by N-acetylcysteine (10 m). l-NAME (10 m) reduced the relaxation to ACh in both groups, although the effect was lower in the trained group (in mean ± SEM, 39 ± 2% vs. 28 ± 3%). Physical training did not modify the relaxation to ACh in femoral arteries, although the response to l-NAME was lower in the trained group (in mean ± SEM, 41 ± 5% vs. 17 ± 2%). Charybdotoxin (10 m) plus apamin (10 m) further reduced the maximal relaxation to ACh only in the trained group. The remaining relaxation in both carotid and femoral arteries was abolished by KCl (2 × 10 m) and BaCl (3 × 10 m) plus ouabain (10 m) in both groups. Physical training decreased eNOS expression in both carotid and femoral arteries and Cu/Zn and Mn-SOD expression only in the carotid artery. BKCa channels were overexpressed in the trained group in the femoral artery. In conclusion, chronic exercise induces endothelial dysfunction in the carotid artery as a result of oxidative stress. In the femoral artery, it modifies the vasodilator pathways, enhancing the participation of BKCa channels, thus compensating for the impairment of NO-mediated vasodilatation.

Impact of Sex and Exercise on Femoral Artery Function: More Favorable Adaptation in Male Rats

“…Marchio et al investigated the effect of long-term training on femoral arteries in male New Zealand white rabbits. In accordance with our results, during the relaxation test with Ach, trained and sedentary groups did not demonstrate differences [ 26 ]. Male Sprague Dawley rats also showed no alterations in response to Ach in a previous study [ 27 ].…”

Development and validation of a carotid atherosclerosis risk prediction model based on a Chinese population

“…The role of exercise in CAS remains controversial. A 6-year clinical trial showed that aerobic physical activity did not slow the progression of CAS ( 27 ) and might contribute to carotid endothelial injury ( 28 ). However, some studies have shown that lack of exercise is a risk factor for CAS ( 11 , 26 ), and aerobic exercise could help combat carotid intima-media thickening in obese patients ( 29 ).…”

Exercise Training Protocols in Rabbits Applied in Cardiovascular Research

“…In general, the protocols for exercise training in rabbits ( Table 2 ) begin with an adaptation phase for the animal, called the familiarization period. This period varies from 3 days [ 34 ], 4 days [ 35 , 36 ], or 1 week [ 31 , 32 , 33 , 37 , 38 ], to several weeks [ 24 , 29 , 39 , 40 , 41 ]. These adaptation periods should be constantly monitored (observation and accompaniment) to avoid the animals running inappropriately or stopping during the execution of the training protocol [ 35 ].…”

“…Each session is divided into 6 exercise intervals. The animals run for 4 min at a speed, depending on the study, of 0.33 m/s [ 21 , 36 ] or 0.5 m/s [ 35 ], separated by a 1 min rest between each run.…”

“…In fact, few studies used California rabbits [ 43 , 44 ] and Pannon rabbits [ 42 , 49 ], compared to the vast majority of studies and protocols using New Zealand white rabbits. [ 24 , 33 , 35 , 36 , 41 , 46 , 47 , 52 , 54 , 56 , 57 ].…”