Physical Factors of Regulation

Vanhoutte, Paul M.

doi:10.1002/cphy.cp020216

Cited by 60 publications

(59 citation statements)

References 229 publications

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“…Another strategy to avoid or tolerate internal ice formation is indeed reducing the volume of circulating blood (53)(54)(55). This strategy, however, deprives internal organs of oxygen and triggers a burst of reactive oxygen species during seasonal temperature recovery (51).…”

Section: Resultsmentioning

confidence: 99%

Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subarctic environments

Librado

Sarkissian

Ermini

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

153

120

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Yakutia, Sakha Republic, in the Siberian Far East, represents one of the coldest places on Earth, with winter record temperatures dropping below −70°C. Nevertheless, Yakutian horses survive all year round in the open air due to striking phenotypic adaptations, including compact body conformations, extremely hairy winter coats, and acute seasonal differences in metabolic activities. The evolutionary origins of Yakutian horses and the genetic basis of their adaptations remain, however, contentious. Here, we present the complete genomes of nine present-day Yakutian horses and two ancient specimens dating from the early 19th century and ∼5,200 y ago. By comparing these genomes with the genomes of two Late Pleistocene, 27 domesticated, and three wild Przewalski's horses, we find that contemporary Yakutian horses do not descend from the native horses that populated the region until the mid-Holocene, but were most likely introduced following the migration of the Yakut people a few centuries ago. Thus, they represent one of the fastest cases of adaptation to the extreme temperatures of the Arctic. We find cisregulatory mutations to have contributed more than nonsynonymous changes to their adaptation, likely due to the comparatively limited standing variation within gene bodies at the time the population was founded. Genes involved in hair development, body size, and metabolic and hormone signaling pathways represent an essential part of the Yakutian horse adaptive genetic toolkit. Finally, we find evidence for convergent evolution with native human populations and woolly mammoths, suggesting that only a few evolutionary strategies are compatible with survival in extremely cold environments. The Yakutian horse is the most northerly distributed horse on the planet and certainly the most resistant to cold. In contrast to SignificanceYakutia is among the coldest regions in the Northern Hemisphere, showing ∼40% of its territory above the Arctic Circle. Native horses are particularly adapted to this environment, with body sizes and thick winter coats minimizing heat loss. We sequenced complete genomes of two ancient and nine present-day Yakutian horses to elucidate their evolutionary origins. We find that the contemporary population descends from domestic livestock, likely brought by early horse-riders who settled in the region a few centuries ago. The metabolic, anatomical, and physiological adaptations of these horses therefore emerged on very short evolutionary time scales. We show the relative importance of regulatory changes in the adaptive process and identify genes independently selected in cold-adapted human populations and woolly mammoths.

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Section: Resultsmentioning

confidence: 99%

Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subarctic environments

Librado

Sarkissian

Ermini

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

153

120

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“…In isolated preparations of vessels from a number of species, heating from 37 to 40-42°C increases vascular muscle tone and spontaneous contraction frequency (Vanhoutte & Lorenz, 1970;Vanhoutte & Shepherd, 1970;Millard & Reite, 1975;Vanhoutte, 1980;Cooke, Shepherd & Vanhoutte, 1984). Warming appears to increase the rate of tension development, increase adenosine triphosphatase activity and enhance metabolism in vascular smooth muscle (Vanhoutte, 1980). Heating from 37 to 48°C also causes an increase in passive wall tension in isolated preparations of rat aorta (McMeeken & Bell, 1984) and rat mesenteric bed (McMeeken, 1987).…”

Section: Discussionmentioning

confidence: 99%

Effects of selective blood and tissue heating on blood flow in the dog hindlimb

McMeeken

Bell²

1990

Experimental Physiology

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SUMMARYThis study investigated the effects of independent and combined heating of blood and tissue to 40-44 'C on femoral blood flow in the hindlimb of the anaesthetized dog. An increase in arterial blood temperature by means of an extracorporeal circuit increased femoral vascular resistance. An increase in limb tissue temperature, induced by external hot packs, decreased femoral vascular resistance. These responses occurred both before and after sympathetic blockade. Neither blood heating nor tissue heating affected the hyperaemic response to exercise. When blood and tissue heating were combined, femoral vascular resistance remained unaffected. We conclude that changes in blood temperature do not contribute to the hyperaemic effect of limb warming and that exercise combined with limb warming is no more effective as a therapeutic tool for promoting limb flow than exercise alone.

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“…6) (Bohr & Webb, 1978;Godfraind & Morel, 1978). The depressant effect of cooling on K+-evoked responses is not specific for cutaneous vessels but has also been observed in other systemic vessels (Keatinge, 1964;Vanhoutte & Shepherd, 1970;Peiper, Griebel & Wende, 1971, Andersson, Hellstrand, Johansson & Ringberg, 1972;Godfraind & Kaba, 1972;Janssens & Vanhoutte, 1978); an important component of this depression is a decrease in membrane permeability for Ca2+ (see Vanhoutte, 1980). At 5 IC, high concentrations of K+ still cause significant increases in tension of the canine saphenous vein confirming this observation on isolated arteries (Keatinge, 1964).…”

Section: Unstimulated Preparationsmentioning

confidence: 95%

The effect of profound cooling on adrenergic neurotransmission in canine cutaneous veins.

Rusch¹,

Shepherd²,

Vanhoutte³

1981

The Journal of Physiology

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1. Experiments were performed to investigate how profound cooling affects adrenergic neurotransmission and vascular smooth muscle reactivity in isolated saphenous veins of the dog. 2. Cooling from 37 to 5 degrees C caused progressive depression of the contractile responses to high K+ solutions, illustrating the direct inhibitory effect of cooling on depolarization‐induced contraction of the venous smooth muscle cells. 3. During prolonged cooling to 20, 15 and 10 degrees C, the contractile response to exogenous norepinephrine (10(‐8)‐10(‐6) M) was augmented compared to that at 37 degrees C. At 5 degrees C responses up to 10(‐7) M were also augmented, but those at higher concentrations were depressed. When veins contracted with 2 x 10(‐6) M‐norepinephrine were cooled to 20, 15, 10 and 5 degrees C, there was a further increase in tension; this increase slowly subsided to control values at 5 degrees C but was sustained at the other temperatures. 4. Cooling to 20 and 15 degrees C augmented the contraction caused by low but not high frequencies of electrical stimulation of the adrenergic nerve endings. Further cooling to 10 degrees C depressed, and at 5 degrees C abolished the response, demonstrating that profound cooling interrupted adrenergic neurotransmission. 5. In rings stimulated electrically at a low frequency (0.5 Hz), warming from 7 to 9 degrees C or from 9 to 11 degrees C, caused marked increases in tension. This may be explained by the combination of resumption of adrenergic neurotransmission and the increased responsiveness of the cutaneous venous smooth muscle cells to adrenaline. 6. The combination of enhanced affinity for noradrenaline combined with inhibition of neurotransmitter disposition probably permits the cutaneous veins to remain constricted during exposure to severe cold.

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Physical Factors of Regulation

Cited by 60 publications

References 229 publications

Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subarctic environments

Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subarctic environments

Effects of selective blood and tissue heating on blood flow in the dog hindlimb

The effect of profound cooling on adrenergic neurotransmission in canine cutaneous veins.

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