Better statistical regularity with aging? Age-related difference in the neural processing of idioms

Aging significantly affects reflex cardiovascular (CV) responses to induced muscular contraction in anesthetized dogs. To further investigate whether age-related changes in alpha-adrenergic-mediated responses to muscular contraction contribute to these previously reported age-related changes in CV responses associated with advanced age, hemodynamic and regional blood flow (BF) responses at baseline and during hindlimb contraction (HLC) were evaluated both before and after alpha-blockade (alpha-AB) in older (8-14 yr old) and in younger (2-3 yr old) beagles during alpha-chloralose anesthesia. alpha-AB with phentolamine resulted in significant (P < 0.05) reductions in mean arterial pressure before and during HLC, regardless of age. However, age-related differences in the systemic vascular resistance, cardiac output, and stroke volume responses to HLC, observed before alpha-AB, were eliminated after phentolamine as the result of an age-related difference in each of these responses to alpha-AB. Baseline BF (microspheres) was unchanged after alpha-AB in seven of eight abdominal organs, regardless of age. However, reductions in BF during HLC were attenuated in seven of eight abdominal organs in the younger dogs after alpha-AB, but in none of these organs in the older dogs, indicative of diminished alpha-mediated vasoconstriction in these organs in the older dogs during HLC. Furthermore, the age-related difference in the combined BF reduction to all eight abdominal organs before alpha-AB was eliminated after alpha-AB. Finally, BF increases to two of four contracting muscles, as well as the combined increase in blood flow to all four contracting muscles, were attenuated after alpha-AB, regardless of age. These results demonstrate that alpha-blockade eliminates many of the age-related differences in CV responses to HLC observed before alpha-AB and suggest that alpha-adrenergic-mediated responses to HLC change with age in beagles.

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AN AGE-RELATED DIFFERENCE IN THE BILL DEPTH OF HERRING GULLS LARUS ARGENTATUS

Ibis ◽

10.1111/j.1474-919x.1981.tb04054.x ◽

2008 ◽

Vol 123 (4) ◽

pp. 499-502 ◽

Cited By ~ 27

Author(s):

J. C. Coulson ◽

N. Duncan ◽

C. S. Thomas ◽

P. Monaghan

Keyword(s):

Larus Argentatus ◽

Herring Gulls ◽

Related Difference ◽

Age Related

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An age-related difference in hyperoxia lethality: role of lung antioxidant defense mechanisms

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1995.268.4.l539 ◽

1995 ◽

Vol 268 (4) ◽

pp. L539-L545 ◽

Cited By ~ 3

Author(s):

A. T. Canada ◽

L. A. Herman ◽

S. L. Young

Keyword(s):

Defense Mechanisms ◽

Antioxidant Defense ◽

Fischer 344 Rats ◽

Fischer 344 ◽

Related Difference ◽

Age Related ◽

65 H ◽

Old Rats ◽

Gpx Activity

The role of animal age in the lethal response to > 98% oxygen has been extensively studied, with the observation that neonatal rats were resistant while mature animals were sensitive. Antioxidant enzymes increased during the oxygen exposure in neonatal but not in mature rats, suggesting they were important in the age-related toxicity difference. Because no studies had compared the response of mature and old rats to hyperoxia, we exposed Fischer 344 rats, aged 2 and 27 mo, to > 98% oxygen. Unexpectedly, the old rats lived significantly longer than young, 114 and 65 h, respectively. No histopathological differences were found to explain the results. Of the antioxidants, only glutathione peroxidase (GPx) activity was higher in the lungs of nonexposed old rats. Superoxide dismutase (SOD) was higher in the young, results opposite those expected if SOD was important in the lethality difference. No antioxidant induction occurred in the old oxygen-exposed rats. These results suggest that although there may be a role for GPx, mechanisms in addition to antioxidant protection and inflammation are likely responsible for the age-related difference in hyperoxia lethality.

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