Key result
High-altitude native guinea pigs had lower heart rate response to isoproterenol and beta-adrenergic receptor density (P<0.05), which partially reversed after 5 weeks at sea level.
Why the study?
The regulation and reversibility of autonomic control in the heart of a typical high-altitude native animal were not well characterized.
Does exposure to hypoxia or normoxia alter autonomic control and cardiac receptor regulation in Andean guinea pigs?
Does exposure to hypoxia or normoxia alter autonomic control and cardiac receptor regulation in Andean guinea pigs?
The study demonstrates differential regulation and reversibility of autonomic control in the guinea pig heart in response to high altitude hypoxia and sea level normoxia.
Guinea pig findings should not alter clinical hypoxia management; leaves open translational relevance of reversible beta-adrenergic changes to humans.
León-Velarde, Fabiola, Jean-Paul Richalet, Juan-Carlos Chavez, Rachid Kacimi, Maria Rivera-Chira, José-Antonio Palacios, and Daniel Clark. Hypoxia- and normoxia-induced reversibility of autonomic control in Andean guinea pig heart. J. Appl. Physiol. 81(5): 2229–2234, 1996.—We herein describe the regulation of cardiac receptors in a typical high-altitude native animal. Heart rate response to isoproterenol (HRIso) (beats ⋅ min−1⋅ mg Iso ⋅ kg−1) and atropine, the density of β-adrenergic (βAR) and muscarinic (M2) receptors, and the ventricular content of norepinephrine (NE) and dopamine (DA) were studied in guinea pigs ( Cavia porcellus). Animals native to Lima, Peru (150 m) were studied at sea level (SL) and after 5 wk at 4,300-m altitude (SL-HA). Animals native to Rancas [Pasco, Peru (4,300 m)] were studied at high altitude (HA) and after 5 wk at SL (HA-SL). HA animals had a lower HRIso, maximum number of βARbinding sites (Bmax), βARdissociation constant ( Kd), NE, and DA ( P < 0.05) and a higher M2Bmax( P < 0.001) when compared with the SL group. HA-SL showed an increase of the HRIso, βARKd, and NE ( P < 0.05) and a decrease of the M2Bmaxand Kd( P < 0.0001) when compared with the HA group. The present study demonstrates the differential regulation and reversibility of the autonomic control in the guinea pig heart.
No takes yet. Share an insight, caveat, or question.
Lèon‐Velarde et al. (1996) studied High-altitude hypoxia adaptation. High altitude (hypoxia) and sea level (normoxia) exposure vs. Native altitude controls was evaluated on Heart rate response to isoproterenol, density of beta-adrenergic and muscarinic receptors, and ventricular content of norepinephrine and dopamine (p=<0.05). High-altitude native guinea pigs had lower heart rate response to isoproterenol and beta-adrenergic receptor density (P<0.05), which partially reversed after 5 weeks at sea level.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: