Abstract
The ventilatory response to CO 2 changes as a function of neonatal development. In rats, a ventilatory response to CO 2 is present in the first 5 days of life, but this ventilatory response to CO 2 wanes and reaches its lowest point around postnatal day 8. Subsequently, the ventilatory response to CO 2 rises towards adult levels. Similar patterns in the ventilatory response to CO 2 are seen in some other species, although some animals do not exhibit all of these phases. Different developmental patterns of the ventilatory response to CO 2 may be related to the state of development of the animal at birth. The triphasic pattern of responsiveness (early decline, a nadir, and subsequent achievement of adult levels of responsiveness) may arise from the development of several processes, including central neural mechanisms, gas exchange, the neuromuscular junction, respiratory muscles and respiratory mechanics. We only discuss central neural mechanisms here, including altered CO 2 sensitivity of neurons among the various sites of central CO 2 chemosensitivity, changes in astrocytic function during development, the maturation of electrical and chemical synaptic mechanisms (both inhibitory and excitatory mechanisms) or changes in the integration of chemosensory information originating from peripheral and multiple central CO 2 chemosensory sites. Among these central processes, the maturation of synaptic mechanisms seems most important and the relative maturation of synaptic processes may also determine how plastic the response to CO 2 is at any particular age.
Original language | American English |
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Journal | Respiratory Physiology & Neurobiology |
Volume | 149 |
DOIs | |
State | Published - Nov 15 2005 |
Keywords
- Mammals
- Tidal volume
- Ventilation
Disciplines
- Medical Cell Biology
- Medical Neurobiology
- Medical Physiology
- Medical Sciences
- Medicine and Health Sciences
- Neurosciences
- Physiological Processes