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Regional circulatory responses to hindlimb work in developing swine
1Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, N.Y.
Biology of the Neonate
|January 1, 1990
Summary
Hindlimb work in young swine causes age-dependent circulatory changes. Neonates redistribute blood flow, while older animals maintain autoregulation, reflecting neural and autoregulatory control balances.
Area of Science:
- Physiology
- Cardiovascular Research
- Developmental Biology
Background:
- Understanding circulatory adjustments during physical exertion is crucial for developmental physiology.
- The interplay between neural and autoregulatory mechanisms in controlling regional blood flow is not fully elucidated in young mammals.
Purpose of the Study:
- To investigate the circulatory effects of hindlimb work in swine across different age groups (neonatal to 1 month).
- To determine the role of neural stimulation and autoregulation in regional blood flow distribution during increased oxygen demand.
Main Methods:
- Studied 29 anesthetized swine (1 day to 1 month old) using pentobarbital.
- Measured femoral, renal, and intestinal blood flow, resistance, and autoregulation during varying hindlimb oxygen consumption levels.
- Assessed circulatory responses before and during distal sciatic nerve stimulation.
Main Results:
- Increased oxygen consumption led to hyperemia in all age groups.
- Enhanced oxygen extraction occurred only in older animals (2 weeks and 1 month), without autoregulation.
- Neonates showed blood flow redistribution from kidney and intestine; older animals maintained renal and intestinal autoregulation.
Conclusions:
- Hindlimb work elicits age-related adjustments in regional blood flow in swine.
- These adjustments highlight the balance between neural control and autoregulation during development.
- The findings provide insights into the maturation of circulatory control mechanisms.