Biomaterial Database

Postnatal development of CO2-O2 interaction in the rat carotid body in vitro. 1995

D R Pepper, and R C Landauer, and P Kumar

Department of Physiology, Medical School, University of Birmingham, UK.

1. The effect of PCO2 upon the discharge response to changes in PO2 (between ca 450 and 30 mmHg) was observed in adult (> 5 weeks old) and neonatal (5-7 days old) rat carotid body chemoreceptors using an in vitro, superfused preparation. 2. In both adult and neonatal rats, regression analysis revealed that increasing PCO2 was without effect upon the shape of the PO2-response curves (P > 0.30), but did cause an upward shift in the position of the curves, as indicated by a significant increase in the baseline chemoreceptor discharge during hyperoxia (0.22 +/- 0.02% maximum discharge per mmHg PCO2, P < 0.001, and 0.25 +/- 0.07% maximum discharge per mmHg PCO2, P < 0.005, respectively). However, whilst increasing PCO2 caused a significant rightward shift of the response curves in adults (0.75 +/- 0.23 mmHg PO2 per mmHg PCO2; P < 0.005), it was without effect in neonates (0.21 +/- 0.22 mmHg PO2 per mmHg PCO2; P > 0.200). Thus increasing levels of hypoxia increased CO2 chemosensitivity in adult but not in neonatal rats as shown by multiple regression analysis of the CO2-response curves which revealed a significant interaction between PCO2 and PO2 for adult (P < 0.010) but not for neonatal (P > 0.150) rats. 3. We suggest that the previously reported maturation of peripheral chemoreceptor hypoxic sensitivity (resetting) may be due to the postnatal emergence of a significant degree of interaction between PCO2 and PO2 at the level of the peripheral chemoreceptor and/or its afferent innervation.

UI	MeSH Term	Description	Entries
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D012044	Regression Analysis	Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.	Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002344	Carotid Body	A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control.	Glomus Caroticum,Bodies, Carotid,Body, Carotid,Caroticum, Glomus,Carotid Bodies
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006935	Hypercapnia	A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000831	Animals, Newborn	Refers to animals in the period of time just after birth.	Animals, Neonatal,Animal, Neonatal,Animal, Newborn,Neonatal Animal,Neonatal Animals,Newborn Animal,Newborn Animals