Gill Blood Flow Control

Nilsson, Stefan; Sundin, Lena

doi:10.1016/s1095-6433(97)00397-8

Cited by 59 publications

(31 citation statements)

References 102 publications

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“…64 In addition to serotonergic neurons, nonneuronal 5-HT immunopositive cells, namely, neuroepithelial cells (NECs), have been found in the efferent part of teleost gill filaments. 65 NECs displaying 5-HT immunoreactivity were detected in all fish species examined, including sturgeon (Acipenser baeri), a nonteleost, while in rainbow trout an additional 5-HT immunopositive cell type was observed and described as polymorphous granular cells. 64 In trout gill filaments, these two cell types have been designated as possible sites for indoleamine synthesis based on immunohistochemical experiments using relevant polyclonal antibodies, which also revealed the intracellular presence of 5-HT as well as the metabolite 5-methoxytryptamine.…”

Section: -Ht In the Gillsmentioning

confidence: 96%

Physiological Endpoints for Potential SSRI Interactions in Fish

Kreke

Dietrich

2008

Critical Reviews in Toxicology

115

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Selective serotonin reuptake inhibitors (SSRIs) are among the pharmaceutical compounds frequently detected in sewage treatment plant effluents and surface waters, albeit at very low concentrations, and have therefore become a focus of interest as environmental pollutants. These neuroactive drugs are primarily used in the treatment of depression but have also found broader use as medication for other neurological dysfunctions, consequently resulting in a steady increase of prescriptions worldwide. SSRIs, via inhibition of the serotonin (5-hydroxytryptamine, 5-HT) reuptake mechanism, induce an increase in extracellular 5-HT concentration within the central nervous system of mammals. The phylogenetically ancient and highly conserved neurotransmitter and neurohormone 5-HT has been found in invertebrates and vertebrates, although its specific physiological role and mode of action is unknown for many species. Consequently, it is difficult to assess the impact of chronic SSRI exposure in the environment, especially in the aquatic ecosystem. In view of this, the current knowledge of the functions of 5-HT in fish physiology is reviewed and, via comparison to the physiological role and function of 5-HT in mammals, a characterization of the potential impact of chronic SSRI exposure on fish is provided. Moreover, the insight on the physiological function of 5-HT strongly suggests that the experimental approaches currently used are inadequate if not entirely improper for routine environmental risk assessment of pharmaceuticals (e.g., SSRIs), as relevant endpoints are not assessed or impossible to determine.

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Section: -Ht In the Gillsmentioning

confidence: 96%

Physiological Endpoints for Potential SSRI Interactions in Fish

Kreke

Dietrich

2008

Critical Reviews in Toxicology

115

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“…These include hyperventilation, decreased heart rate and changes in gill vascular resistance (Sundin and Nilsson, 1997;Nilsson and Sundin, 1998;Burleson and Milsom, 2003). A group of neurosecretory paraneurons, called neuroepithelial cells (NECs), are found in the primary epithelium of the gill filaments, where they are exposed to the incident flow of water over the gills during ventilation (see Fig.…”

Section: Role Of Innervation In O 2 Sensingmentioning

confidence: 99%

“…Innervation of the contractile segment of the eFA by filament neurons has been previously described in other species and may operate through serotonergic or cholinergic mechanisms DunelErb et al, 1989). Furthermore, vasoconstriction of the proximal region of the eFA appears to occur during hypoxia (Sundin and Nilsson, 1997) and may contribute to the hypoxic increase in gill vascular resistance observed in teleosts (Nilsson and Sundin, 1998;Smith et al, 2001). A subsequent elevation in lamellar perfusion pressure may lead to a process known as 'lamellar recruitment' that may underlie perfusion of distal lamellae (which are apparently not normally utilized) during periods of hypoxia to increase respiratory surface area and gas exchange (Booth, 1978;Booth, 1979;Sundin and Nilsson, 1997).…”

Section: Role Of Innervation In Vascular Control During Hypoxiamentioning

confidence: 99%

New developments on gill innervation: insights from a model vertebrate

Jonz

Nurse

2008

Journal of Experimental Biology

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SummaryThe fish gill is a highly specialized and complex organ that performs a variety of important physiological functions. In this article, we briefly review the innervation of important structures of the branchial region, such as the gill filaments, respiratory lamellae and pseudobranch, and discuss the physiological significance of this innervation within the context of homeostatic functions of the gill, such as oxygen sensing and ion regulation. Studies in zebrafish utilizing techniques of confocal microscopy and immunolabelling, with specific antibodies against neuronal markers, have recently led to the characterization of innervation patterns in the gills not attained with traditional techniques of histochemistry and electron microscopy. We will discuss the association of putative sensory nerve fibres with O 2 -chemoreceptive neuroepithelial cells and the implications of dual sensory pathways for cardiorespiratory and vascular control. In addition, the idea of the neural control of ion regulation in the gill based on the apparent innervation of mitochondria-rich cells, and the role of innervation in the pseudobranch, will be presented.

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“…Mott (1951) obtained the same results using a similar experimental preparation in the eel Anguilla anguilla. These early observations pointed out the gills as the primary site for baroreceptor sensitivity in fish, a fact that still seems to be the general consensus (Nilsson and Sundin, 1998).…”

Section: )mentioning

confidence: 99%

Baroreflex mediated control of heart rate and vascular capacitance in trout

Sandblom

Axelsson

2005

Journal of Experimental Biology

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SUMMARY The baroreflex was triggered by altering branchial blood pressure with pre-and post-branchial occlusions for 30 s in rainbow trout Oncorhynchus mykiss. The cardiac limb of the baroreflex was monitored by continuous heart rate (fH) measurements. Responses of venous capacitance vessels were assessed, immediately following either occlusion, by measuring mean circulatory filling pressure (MCFP). Arterial responses were evaluated as the change in dorsal aortic blood pressure(Pda) before and after pre-branchial occlusion. In untreated fish pre-branchial occlusion resulted in tachycardia(62.4±2.4 to 69.1±1.7 beats min–1), decreased venous capacitance reflected as an increase in MCFP (0.17±0.03 to 0.27±0.03 kPa) and increased Pda (4.0±0.2 kPa compared to 3.2±0.1 kPa before occlusion). Post-branchial occlusion somewhat reversed the responses since fH decreased(62.4±2.4 to 53.0±3.1 beats min–1), whereas MCFP remained unaltered. Treatment with the α-adrenergic blocker prazosin (1 mg kg–1) increased resting MCFP to 0.33±0.03 kPa and appeared to abolish both venous and arterial responses to branchial occlusion. Subsequent atropine treatment (1.2 mg kg–1) abolished all chronotropic responses. We present for the first time ample evidence for baroreflex-mediated control of cardiovascular homeostasis, including both the chronotropic and the vascular limb of the baroreflex in an unanaesthetized fish. Furthermore, a novel technique to cannulate and occlude the dorsal aorta, using a Fogarty thru-lumen embolectomy catheter, is explained.

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Gill Blood Flow Control

Cited by 59 publications

References 102 publications

Physiological Endpoints for Potential SSRI Interactions in Fish

Physiological Endpoints for Potential SSRI Interactions in Fish

New developments on gill innervation: insights from a model vertebrate

Baroreflex mediated control of heart rate and vascular capacitance in trout

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