Comparative physiology in high altitudes

Abstract

Altitude is a component of the physical environment to which animals show adjustments. Oxygen pressure and temperature decrease with increasing altitudes, and to both of these factors organisms respond in a variety of ways. As temperature varies with latitude and seasons as well as with altitude, oxygen pressure becomes the more specific factor in the study of effects of high altitudes.When man first climbs to high altitudes he has many of the sensations experienced in seasickness. He longs for his native habitat, wonders if he will survive the experience, and marvels at the ability of some of his fellows to enjoy food. I n due time, whether the environment is a rolling ship or a lofty mountain, acclimatization usually occurs. The mechanism of the adaptive process in the first case is not understood; in the second case many changes which take place during adaptation are familiar but their significance is not

Anxiolytic-Like Effects of (O-Methyl)-N-2,6-dihydroxybenzoyl-tyramine (Riparin III) from Aniba riparia (NEES) MEZ (Lauraceae) in Mice

“…behavioral and peripheral changes presumed to accompany high sympathetic nervous activity. 17) Thus, an analogy, if not a homology, between anxiety in humans and rodents may be assumed.…”

Hemoglobin–oxygen affinity in high-altitude vertebrates: is there evidence for an adaptive trend?

“…the independent colonization of high-altitude environments by multiple species) complement insights derived from controlled laboratory experiments. For example, comparative studies have documented that high-altitude rodents often have higher Hb and/or blood O 2 affinities than their lowland relatives (Hall et al, 1936;Bullard et al, 1966;Ostojic et al, 2002;Storz, 2007;Storz et al, 2009Storz et al, , 2010aNatarajan et al, 2013Natarajan et al, , 2015aJensen et al, 2016), and these observations complement the results of experiments demonstrating that increases in blood-O 2 affinity enhance tissue O 2 delivery and measures of physiological performance in rodents subjected to environmental hypoxia (Eaton et al, 1974;Turek et al, 1978a,b;Chappell and Snyder, 1984). Such consilience of evidence from comparative and experimental studies can greatly strengthen conclusions about the adaptive significance of evolutionary changes in Hb-O 2 affinity.…”

“…In comparative physiology, a fairly well-accepted empirical generalization is that vertebrate taxa that are native to highaltitude environments tend to have elevated hemoglobin (Hb)-O 2 affinities in comparison with lowland relatives (Hall et al, 1936;Bullard, 1972;Lenfant, 1973;Bunn, 1980;Monge and León-Velarde, 1991;Weber, 1995Weber, , 2007Storz, 2007;Powell and Hopkins, 2010;Storz et al, 2010b). However, this putative trend is based on a relatively small number of case studies, and comparative data have not always been interpreted in a well-informed phylogenetic framework.…”

Myoglobin oxygen affinity in aquatic and terrestrial birds and mammals

“…Sprague-Dawley rats that had their Hb oxygen affinity artificially elevated with sodium cyanate had better survivability and lower experimental heart rates in a hypoxic environment (Eaton et al, 1974). Burrowing rodents that experience hypoxic environments in underground burrows exhibit an increased Hb oxygen affinity (Revsbech et al, 2013) and animals adapted to high altitude, such as bar-headed geese (Anser indicus) (Jessen et al, 1991), vicuña (Vicugna vicugna) (Hall et al, 1936) and deer mice (Peromyscus maniculatus) (Storz et al, 2009) also possess high oxygen affinity Hb compared with their low-altitude counterparts.…”