Dopamine D2 receptor modulation of carotid body type 1 cell intracellular calcium in developing rats

J. L. Carroll, K. M. Boyle, M. J. Wasicko, L. M. Sterni

Research output: Contribution to journalArticle

Abstract

Carotid chemoreceptor type 1 cells release dopamine, which inhibits carotid chemoreceptor activity via dopamine D2 autoreceptors on type 1 cells. Postnatal changes in dopaminergic modulation may be involved in postnatal chemoreceptor development. The present study explores dopaminergic modulation of the intracellular calcium ([Ca2+]i) response to hypoxia in type 1 cells from 1, 3, and 11- to 16-day-old rats. Using fura-2, we studied the effects of quinpirole, a D2 receptor agonist, on type 1 cell [Ca 2+]i response to 90-s hypoxia challenges (Po2 ∼1-2 mmHg). Cells were sequentially exposed to the following challenges: 1) hypoxia control, 2) hypoxia plus quinpirole, and 3) hypoxia plus quinpirole plus sulpiride (D2 receptor antagonist). In the 11- to 16-day-old group, type 1 cell [Ca2+]i increased ∼3 to 4-fold over resting [Ca 2+]i in response to hypoxia. Quinpirole (10 μM) significantly blunted the peak [Ca2+]i response to hypoxia. Repeat challenge with hypoxia plus 10 μM quinpirole in the presence of 10 μM sulpiride partially restored the hypoxia [Ca2+] i response. In sharp contrast to the older aged group, 10 μM quinpirole had minimal effect on hypoxia response of type 1 cells from 1-day-olds and a small but significant effect at 3 days of age. We conclude that stimulation of dopamine D2 receptors inhibits type 1 cell [Ca 2+]i response to hypoxia, consistent with an inhibitory autoreceptor role. These findings suggest dopamine-mediated inhibition and oxygen sensitivity increase with age on a similar time course and do not support a role for dopamine as a major mediator of carotid chemoreceptor resetting.

Original languageEnglish (US)
Pages (from-to)L910-L916
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume288
Issue number5 32-5
DOIs
StatePublished - May 1 2005

Keywords

  • Chemoreceptor
  • Development
  • Dopamine receptors
  • Hypoxia

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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