Department of Zoology, University of British Columbia, #4200-6270, University Blvd. Vancouver, B.C., V6T 1Z4, Canada.
Department of Zoology, University of British Columbia, #4200-6270, University Blvd. Vancouver, B.C., V6T 1Z4, Canada.
Respir Physiol Neurobiol. 2021 Jun;288:103640. doi: 10.1016/j.resp.2021.103640. Epub 2021 Feb 12.
Burrowing rodents have a blunted hypercapnic ventilatory response compared to non-burrowing rodents, but semi-fossorial ground squirrels and hamsters are not born with this blunted response when raised in room conditions. This study examined the hypercapnic ventilatory response of rats, hamsters, and ground squirrels raised in burrow-like hypercapnia (∼3 % CO) through development (embryonic day 16-18 to postnatal day 30) to determine if chronic hypercapnia exerts any effect on the developing and adult semi-fossorial response. Chronic hypercapnia attenuated the ventilatory response to 5 % CO by 60 % (rats), 150 % (hamsters), and 70 % (squirrels) in newborns when compared to newborns raised in normal conditions. When raised in burrow conditions, squirrels and hamsters reached the blunted adult response ∼8-12 days sooner in development than their room air counterparts, while burrow-reared rats maintained a consistently blunted response until removal from chronic hypercapnia. Our study revealed no lasting effect of chronic hypercarbia on the ventilatory responses to CO in burrowing rodents, but rather a change in the developmental profile such that the blunted adult response was reached earlier in development.
穴居啮齿动物的高碳酸血症通气反应较非穴居啮齿动物迟钝，但在室内条件下饲养的半掘土地松鼠和仓鼠并没有天生具有这种迟钝的反应。本研究通过发育（胚胎第 16-18 天至出生后第 30 天）检查了在类似洞穴的高碳酸血症（约 3% CO）中饲养的大鼠、仓鼠和地松鼠的高碳酸血症通气反应，以确定慢性高碳酸血症对发育和成年半掘土反应是否有任何影响。与在正常条件下饲养的新生儿相比，慢性高碳酸血症使新生儿对 5% CO 的通气反应分别减弱了 60%（大鼠）、150%（仓鼠）和 70%（地松鼠）。当在洞穴条件下饲养时，地松鼠和仓鼠在发育过程中比其在室内空气环境中的对应物更早地达到了迟钝的成年反应，而在慢性高碳酸血症中饲养的大鼠则一直保持着迟钝的反应，直到从慢性高碳酸血症中移除。我们的研究表明，慢性高碳酸血症对穴居啮齿动物对 CO 的通气反应没有持久的影响，而是改变了发育模式，使得迟钝的成年反应在发育过程中更早地达到。
