Inter and intra-species-related differences in the regulation of the cardiac autonomic system.
The heart rate response to isoproterenol (HR-Iso), density and affinity (kd) of beta-adrenergic (beta-AR) and muscarinic (M2) receptors were compared among three rodents with different generation-life histories of confinement and of high altitude exposure. The European guinea pig (Cavia porcellus) (EGp), a laboratory animal that arrived in Europe after the Spanish Conquest of South America and the Peruvian guinea pig (C. porcellus) (PGp), a semi-wild animal that came from the altiplano to sea level at least 25 generations ago, were used for intra-species comparison. Wistar rats (WR) were used for inter-species comparison as representative of a typical sea level laboratory animal. The HR-Iso was lower in EGp than in the PGp. The PGp showed the highest beta-AR density (P < 0.0005) and the highest beta-AR kd values (P < 0.0005) when compared to both EGp and WR groups (beta-AR Bmax (fmol mg-1 prot), WR, 19 +/- 4; Egp, 34 +/- 10; PGp, 74 +/- 15. beta-AR kd (pM), WR, 24 +/- 10; Egp, 17 +/- 7; PGp, 39 +/- 14). In contrast, PGp showed lower M2 receptor density values than the EGp (P < 0.0005). The WR had the highest M2 receptor densities (M2 Bmax (fmol mg-1 prot), WR, 188 +/- 15; Egp, 147 +/- 9; PGp, 118 +/- 6 and M2 kd (pM), WR, 65 +/- 12; Egp, 67 +/- 6; PGp, 92 +/- 2). The inter and intra-species differences found may be related to their respective history of confinement rather than to their history of exposure to high altitude.
León-Velarde
F
F
Universidad Peruana Cayetano Heredia, Dpto. de Ciencias Fisiológicas/Instituto de Investigaciones de la Altura (IIA), Lima, Peru.
Richalet
J P
JP
Chavez
J C
JC
Kacimi
R
R
Rivera-Chira
M
M
Palacios
J A
JA
Clark
D
D
D000531:Altitude; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D000860:Hypoxia / Q000503:physiopathology; D007545:Isoproterenol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism
D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D007545:Isoproterenol