Evidence for a form of adrenergic response to stress in the mollusc Crassostrea gigas

Abstract

Catecholamines and pro-opiomelanocortin (POMC)-derived peptides, some of the central regulators of the stress-response systems of vertebrates, are also present in invertebrates. However, studies are needed to determine how these hormones participate in the organisation of neuroendocrine stress-response axes in invertebrates. Our present work provides evidence for the presence of an adrenergic stress-response system in the oyster Crassostrea gigas. Noradrenaline and dopamine are released into the circulation in response to stress. Storage and release of these hormones take place in neurosecretory cells presenting morphological and biochemical similarities with vertebrate chromaffin cells. Both in vivo and in vitro experiments showed that applications of the neurotransmitters acetylcholine or carbachol caused no significant release of noradrenaline or dopamine. Moreover, the nicotinic antagonists hexamethonium and α -bungarotoxin and the muscarinic antagonist atropine caused no significant inhibition of catecholamine release in stressed oysters. Adrenocorticotropic hormone (ACTH) induced a significant release of noradrenaline, but the release of dopamine in response to ACTH was not significant. These results suggest that, unlike that of vertebrates, the adrenergic stress-response system of oysters is not under the control of acetylcholine and that other factors, such as the neuropeptide ACTH, might control this system.

Proteomic Basis of Stress Responses in the Gills of the Pacific OysterCrassostrea gigas

“…Catecholamine (CA) is one of the hormones to modulate the proximal tubular sodium transport in the mammalian kidney . In oysters, hyposalinity was reported to elicit a significant increase in the expression of two circulating CAs, noradrenaline (NA) and dopamine (DA), whose concentrations peaked at 12 h and lasted up to 72 h of poststress . In contrast, our results showed that hyposalinity could reduce the expression of renalase, which is a secreted amine oxidase to metabolize circulating CAs, indicating that the oyster could reduce the degradation rate of CAs to enhance osmotic stress tolerance.…”

Noradrenaline-Functionalized Hyperbranched Fluoropolymer–Poly(ethylene glycol) Cross-Linked Networks As Dual-Mode, Anti-Biofouling Coatings

“…Oyster hemocytes have been found to express adrenergic receptors (target receptors for NA), and the effects of NA on oyster hemocyte physiology have been well documented. In fact, hemocytes are known to undergo apoptosis (programmed cell death) upon NA stimulation. − Since oysters are a prominent fouling species and their cells express the target receptors, hemocytes make for a good model system to screen NA-conjugated polymer surfaces. , A similar strategy was employed by Gohad et al . to observe interactions between NA-conjugated PHEMA and PMAA polymer brushes and oyster hemocytes .…”

Role of the Neuroendocrine System of Marine Bivalves in Their Response to Hypoxia

“…DA, NE, and E are present in various tissues of mollusks (in particular, bivalves), including the ganglion, hepatopancreas, and hemocytes [ 30 , 57 , 58 , 59 , 60 ]. The source of catecholamines in bivalves is predominantlythe neurosecretory neurons of the central nervous system (CNS) [ 30 , 61 ]; their secretion in hemocytes has also been reported [ 30 , 35 ]. Although DA, NE, and E have been identified in the mollusk CNS [ 30 , 54 ], DA isthe only catecholamine recorded inbivalve ganglia, according to immunohistochemical methods.…”

“…In the CNS, DA-ergic neurons have been found in Mytilus edulis [ 62 ], Placopecten magellanicus [ 59 , 63 ], and Patinopecten yessoensis [ 64 , 65 ]. A number of experimental studies have shown variations in the CA level in the CNS and hemolymph of mollusks exposed to various stress factors [ 61 , 66 , 67 , 68 ].…”