Baserga MC, Bertolotto C, Sola A. Different Doses of Dopamine Have Heterogeneous Effects on Cerebral Hemodynamics and Dopamine Receptors in Young Rabbits as Measured with Near Infrared Spectroscopy.
Neonatology 2005;
87:229-35. [PMID:
15655313 DOI:
10.1159/000083372]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 10/12/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND
Fluctuations in cerebral blood volume and cerebral oxygenation may be important in the pathogenesis of intraventricular hemorrhage and hypoxic-ischemic brain injury in the neonate. The cerebral hemodynamic response to dopamine infusion in premature infants is not well established. The newborn rabbit, a rather immature species at birth, is a suitable model for monitoring the physiological changes of the cerebral circulation.
METHODS
The effect of dopamine upon cerebral hemodynamics and basal ganglia dopaminergic receptors were studied using four different dopamine doses.
RESULTS
No significant changes in near infrared spectroscopy (NIRS) parameters were observed in the animals that received 0.5 (n = 5) and 1 microg/kg/min (n = 4) of dopamine intravenously. In contrast, in those animals that received dopamine at 5 microg/kg/min (n = 7) and 50 microg/kg/min (n = 7), there was a significant decrease in oxygenated hemoglobin. Moreover, this was accompanied by a significant increase in deoxygenated hemoglobin soon after drug infusion. Cerebral blood volume was increased in the group that received 5 microg/kg/min, but significantly decreased in the group that received 50 microg/kg/min. In both groups NIRS parameters returned to baseline values soon after stopping dopamine infusion.
CONCLUSION
Despite evidence of a physiological response, we found no difference in the distribution of dopamine receptors between experimental and control animals. We therefore speculate that dopamine has an effect on the cerebrovasculature that could be mediated by factors other than changes in the basal ganglia dopamine receptors.
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