Noradrenaline modulates hemocyte reactive oxygen species production via beta-adrenergic receptors in the oyster Crassostrea gigas.
Catecholamines (CA) are known to be present in the microenvironment of molluscan immunocytes. In the present study, experiments were conducted to determine the effects of noradrenaline (NA), the principal CA circulating in bivalve hemolymph, on the luminol-dependent chemiluminescence (CL) of oyster Crassostrea gigas hemocytes. Results show that NA had a dose-dependent inhibitory effect on the CL-response at the physiological concentration of 0.1 microM and above. The alpha-adrenoceptor agonist phenylephrine had no significant effect on the CL-response whereas the beta-adrenoceptor agonist isoproterenol mimicked the inhibitory effects of NA on the CL-response. The beta-adrenoceptor antagonist propanolol, but not the alpha-adrenoceptor antagonist prazosin, prevented the negative effects of NA on the CL-response. Taken together, these results show that beta-adrenergic receptors are present at the surface of oyster hemocytes and allow NA to down-regulate the CL-response.
Lacoste
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A
Station Biologique de Roscoff, CNRS, Université Paris VI, INSU, Place Georges Teissier, BP 74, 29682 Roscoff cedex, France. lacoste@sb-roscoff.fr
Malham
S K
SK
Cueff
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A
Poulet
S A
SA
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006434:Hemocytes / Q000187:drug effects* / Q000378:metabolism; D008163:Luminescent Measurements; D009638:Norepinephrine / Q000494:pharmacology / Q000502:physiology*; D010125:Ostreidae / Q000276:immunology*; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D016897:Respiratory Burst / Q000187:drug effects*; D015054:Zymosan / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D017382:Reactive Oxygen Species; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D015054:Zymosan; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin