Dopaminergic mechanisms of neural plasticity in respiratory control: transgenic approaches.
Data supporting the hypothesis that dopamine-2 receptors (D(2)-R) contribute to time-dependent changes in the hypoxic ventilatory response (HVR) during acclimatization to hypoxia are briefly reviewed. Previous experiments with transgenic animals (D(2)-R 'knockout' mice) support this hypothesis (J. Appl. Physiol. 89 (2000) 1142). However, those experiments could not determine (1) if D(2)-R in the carotid body, the CNS, or both were involved, or (2) if D(2)-R were necessary during the acclimatization to hypoxia versus some time prior to chronic hypoxia, e.g. during a critical period of development. Additional experiments on C57BL/6J mice support the idea that D(2)-R are critical during the period of exposure to hypoxia for normal ventilatory acclimatization. D(2)-R in carotid body chemoreceptors predominate under control conditions to inhibit normoxic ventilation, but excitatory effects of D(2)-R, presumably in the CNS, predominate after acclimatization to hypoxia. The inhibitory effects of D(2)-R in the carotid body are reset to operate primarily under hypoxic conditions in acclimatized rats, thereby optimizing O(2)-sensitivity.
Huey
K A
KA
Department of Medicine 0623A, Physiology Division, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0623, USA.
Szewczak
J M
JM
Powell
F L
FL
D000064:Acclimatization / Q000235:genetics / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D000860:Hypoxia / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity / Q000235:genetics / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000502:physiology*; D012196:Review Literature as Topic; D013997:Time Factors
D017448:Receptors, Dopamine D2