Specific [3H]spiperone binding sites in the pituitary of rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus)

1995 ◽  
Vol 73 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Robert J. Omeljaniuk
Keyword(s):  
Rainbow Trout ◽  
Specific Binding ◽  
Developmental Differences ◽  
Pituitary Hormone ◽  
Pars Distalis ◽  
Single Class ◽  
Neurointermediate Lobe ◽  
Goldfish Carassius Auratus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nonspecific Effects

Dopamine, a catecholamine neurohormone, modulates pituitary hormone release in teleost fishes and other vertebrates. The existence and binding parameters of a pituitary dopamine–neuroleptic receptor from trout were examined and compared with those from goldfish. Pituitary homogenate was incubated with [3H]spiperone (D2 antagonist) under several experimental paradigms; incubations were terminated by filtration and bound 3H radioactivity was assessed by liquid scintillation spectroscopy. Specific binding of [3H]spiperone was tissue dependent. Equilibrium displacement analyses using domperidone (D2 antagonist) indicated a single class of binding site (LIGAND) with Kd = 2.49 ± 0.89 μM and a capacity of 3.10 ± 0.45 nmol/mg protein; the goldfish Kd and capacity were both significantly (p < 0.05) larger: Kd = 4.63 ± 0.30 μM and capacity = 20.66 ± 2.03 nmol/mg protein. The Kd and capacity for the trout pars distalis (2.45 ± 0.33 μM and 3.27 ± 0.24 nmol/mg protein, respectively) did not differ significantly (p < 0.05) from that of the neurointermediate lobe (2.50 ± 0.08 μM and 3.58 ± 0.56 nmol/mg protein, respectively). Dopamine D2 receptor ligands differentially displaced [3H]spiperone from the trout pituitary, while D1 ligands, a D4 ligand, and a 5-hydroxytryptamine (5HT2) receptor antagonist had only small nonspecific effects. Comparison of the trout and goldfish pituitary dopamine–neuroleptic receptor indicates conservation of receptor affinity (Kd); however, differences in receptor numbers and in the distribution of receptors between the pars distalis and neurointermediate lobe in the two species may be due in part to species or developmental differences, and may reflect differences in the role(s) and degrees of influence of dopamine in these fishes.Key words: pituitary, dopamine, receptor, rainbow trout, goldfish.

The rainbow trout skeletal muscle β-adrenergic system: characterization and signaling

2003 ◽  
Vol 284 (3) ◽  
pp. R689-R697 ◽  
Author(s):  
Michel B. Lortie ◽  
Thomas W. Moon
Keyword(s):  
Rainbow Trout ◽  
Binding Sites ◽  
Specific Binding ◽  
Adrenergic System ◽  
Camp Production ◽  
Binding Assays ◽  
Single Class ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Adrenergic Antagonist ◽  
Number Of Binding Sites

The presence and functionality of β-adrenoceptors (β-ARs) were examined in red (RM) and white muscle (WM) membranes isolated from the rainbow trout Oncorhynchus mykiss. Specific binding assays revealed the presence of a single class of binding sites with similar affinities in both muscle types ( K d in nM: 0.14 ± 0.03 and 0.18 ± 0.03 for RM and WM, respectively) but with a significantly higher number of binding sites in RM compared with WM (Bmax in fmol/mg protein: 3.22 ± 0.11 and 2.60 ± 0.13, respectively). Selective and nonselective β-adrenergic agonists (β-AAs) and antagonists indicated an atypical β-AR pharmacology. This result may represent a nonmammalian β-AR classification or, more likely, the presence of more than one β-AR subtype in trout muscles with similar affinities that could not be kinetically resolved. Adenylyl cyclase (ACase) assays showed a dose-dependent increase in cAMP production as concentrations of β2-AAs increased in both muscle membranes with significantly higher basal cAMP production in RM compared with WM (cAMP production in pmol cAMP · mg protein−1 · 10 min−1: 24.67 ± 3.06 and 9.64 ± 3.45, respectively). The agonist-induced increase in cAMP production was blocked by the β-adrenergic antagonist propranolol, while the ACase activator forskolin increased cAMP production by 7- to 14-fold above basal and ∼3-fold above all β-AAs tested. This study demonstrated the presence of atypical β2-ARs on RM and WM membranes of trout, suggesting that β2-AAs may be a tool to enhance protein accretion through this signaling pathway.

The relationship between responsiveness and elusiveness of heat-shocked goldfish (Carassius auratus) to attacks by rainbow trout (Oncorhynchus mykiss)

1994 ◽  
Vol 72 (3) ◽  
pp. 423-426 ◽  
Author(s):  
Paul W. Webb ◽  
Hongbao Zhang
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Carassius Auratus ◽  
Prey Capture ◽  
Acclimation Temperature ◽  
Escape Velocity ◽  
Reaction Distance ◽  
Goldfish Carassius Auratus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Relationship

We measured reaction distance, escape velocity, and the apparent looming threshold (ALT) of heat-shocked goldfish (Carassius auratus) attacked by trout (Oncorhynchus mykiss). We tested fish at the acclimation temperature of 15 °C after heat-shocking prey for 2 min at temperatures ranging from 34 to 39 °C. Escape speeds were unaffected by heat shock. Reaction distance decreased from about 21 cm for fish shocked at 35 °C to about 6 cm for those shocked at 39 °C. ALT increased from 0.2 rad∙s−1 for controls to 0.4 rad∙s−1 for goldfish heat-shocked at 39 °C. The elusiveness of prey, E, was measured as the number of attacks required per prey capture. E was related to ALT as: E = 1.29 (±0.47)∙ALT−0.82(±0.25) (mean (±2 SE)). Factors that decrease responsiveness of prey have large effects on the ability of prey to avoid predators.

Possible involvement of somatolactin in the regulation of plasma bicarbonate for the compensation of acidosis in rainbow trout

1997 ◽  
Vol 200 (21) ◽  
pp. 2675-2683
Author(s):  
S Kakizawa ◽  
A Ishimatsu ◽  
T Takeda ◽  
T Kaneko ◽  
T Hirano
Keyword(s):  
Rainbow Trout ◽  
Metabolic Acidosis ◽  
Respiratory Acidosis ◽  
Pituitary Hormone ◽  
Similar Extent ◽  
Acid Infusion ◽  
Control Value ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Blood Ph ◽  
The Difference

Somatolactin is a putative pituitary hormone of the growth hormone/prolactin family in fish. Its function is still unknown. The effects of environmental hypercapnia and hypoxia, acid (HCl) infusion and exhaustive exercise on plasma somatolactin levels were examined in the chronically cannulated rainbow trout to study the possible physiological roles of somatolactin. Respiratory acidosis induced by hypercapnia (2% CO2) did not affect plasma somatolactin level. In contrast, metabolic acidosis induced by acid infusion and exercise increased plasma somatolactin level. Blood pH was depressed to a similar extent by both types of acidosis, whereas plasma [HCO3-] was elevated by respiratory acidosis but reduced by metabolic acidosis. A moderate hypoxia (water PO2 9.3kPa) affected neither acid&shy;base status nor plasma somatolactin level. A more severe hypoxia (water PO2 6.1kPa) resulted in metabolic acidosis accompanied by an apparent rise in plasma somatolactin level, although the difference in somatolactin level from the control value was not statistically significant. Somatolactin immunoneutralization retarded recovery of plasma [HCO3-] following acid infusion. These results indicate that somatolactin is involved in the retention of HCO3- during metabolic acidosis but not in the active accumulation of HCO3- for acid&shy;base compensation of respiratory acidosis in rainbow trout Oncorhynchus mykiss.

Characterisation of the binding of leukotriene B4 to macrophages of the rainbow trout Oncorhynchus mykiss.

1997 ◽  
Vol 200 (1) ◽  
pp. 155-160
Author(s):  
L A Bowden ◽  
S Fiore ◽  
C J Restall ◽  
C N Serhan ◽  
A F Rowley
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Receptor Antagonist ◽  
Head Kidney ◽  
Leukotriene B4 ◽  
Scatchard Analysis ◽  
Single Class ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Kinetics Of ◽  
Dissociation Constant Kd

The binding of leukotriene B4 (LTB4) to macrophages from the head kidney of the rainbow trout Oncorhynchus mykiss was measured. Binding of [3H]LTB4 achieved a steady state after approximately 30 min of incubation and was 30% reversible in the presence of a minimum of 1000-fold excess of LTB4. Scatchard analysis of the kinetics of LTB4 binding over a range of [3H]LTB4 concentrations indicated the existence of only a single class of receptor with a dissociation constant, KD, of 0.14 nmol l-1 and a maximum receptor density, Bmax, of approximately 17,800 sites per macrophage. The LTB4 receptor antagonist LY223982 was ineffective in inhibiting the binding of [3H]LTB4 to trout macrophages, although another receptor antagonist, LTB4-dimethylamide, displaced a maximum of 25% of the total binding. LTB5 was equally effective as LTB4 at displacing [3H]LTB4, while other eicosanoids tested were without significant effect. It is suggested that the putative receptors for LTB4 on trout macrophages are similar to the high-affinity receptors for this compound reported to occur on mammalian granulocytes, although any structural similarities of the binding sites await further investigation.

Pituitary control of pigmentation in xanthic, moor, and white Carassius auratus L

1977 ◽  
Vol 55 (2) ◽  
pp. 456-464 ◽  
Author(s):  
J. F. Leatherland ◽  
R. Bekolay ◽  
R. S. McLean ◽  
D. Brown
Keyword(s):  
Luteinizing Hormone ◽  
Carassius Auratus ◽  
Follicle Stimulating Hormone ◽  
Pars Distalis ◽  
Neurointermediate Lobe ◽  
Goldfish Carassius Auratus ◽  
Orange Colour ◽  
Stimulating Hormone

After hypophy sectomy some of the melanophores in moor fantail goldfish (Carassius auratus L.) underwent lysis and the remaining cells showed melanin aggregation. The orange colour in xanthic. moor, and white fantail varieties of goldfish 'pales' after hypophysectomy. Homogenates of whole pituitary, pars distalis, or neurointermediate lobe tissue given as intraperitoneal injections effected a marked increase in the melanophore index in hypophysectomized moor fantails and intensified the orange colour in hypophy sectomized moor and xanthic fantails.Ovine prolactin, ovine thyrotrophs (TSH), ovine somatotrophs (STH), and a combination of ovine luteinizing hormone (LH) and porcine follicle-stimulating hormone (FSH) were effective in increasing the melanophore index in hypophy sectomized moor fantails. Of these four preparations the LH–FSH combination was the most potent. Saline and thyroxine were without effect.Ovine prolactin, ovine STH. and a combination of ovine LH and porcine FSH restored the orange colour of hypophysectomized xanthic and moor fantails. Of these three preparations the LH–FSH was most potent. Saline, ovine TSH. and thyroxine were without effect.Differences were found in the apparent activity of prolactin, thyrotroph, gonadotroph, and putative melanocyte-stimulaling hormone (MSH) cells in the pituitaries of the three varieties of goldfish but these could not be directly correlated with pigmentation differences between the groups.

Levels of steroids, including cortisol and 17α,20β-dihydroxy-4-pregnen-3-one, in plasma, seminal fluid, and urine of Pacific herring (Clupea hareng us pallasi) and North Sea plaice (Pleuronectes platessa L.)

1991 ◽  
Vol 69 (1) ◽  
pp. 111-116 ◽  
Author(s):  
A. P. Scott ◽  
A. V. M. Canario ◽  
Nancy M. Sherwood ◽  
Carol M. Warby
Keyword(s):  
Rainbow Trout ◽  
Seminal Fluid ◽  
Salmo Gairdneri ◽  
Pacific Herring ◽  
Pleuronectes Platessa ◽  
Goldfish Carassius Auratus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Plasma Séminal ◽  
High Concentrations ◽  
Urine Contamination

In an accompanying paper we report that herring milt contains high concentrations of conjugated cortisol and 17α,20β-dihydroxy-4-pregnen-3-one. We suggest that one source of these steroids was the urine, which could have become mixed with the milt during the hand-stripping procedure. In the present study, samples of hand-stripped milt from several other species, plaice (Pleuronectes platessa), dab (Limanda limanda), flounder (Platichthys flesus), goldfish (Carassius auratus), and rainbow trout (Oncorhynchus mykiss, formerly Salmo gairdneri), were assayed for free and conjugated cortisol. Uncontaminated samples of plasma, seminal fluid, and urine of male herring and plaice were also assayed for free and conjugated cortisol (both species), 17α,20β-dihydroxy-4-pregnen-3-one (herring only), 17α,20α-dihydroxy-4-pregnen-3-one, and 3α,17α,21-trihydroxy-5β-pregnan-20-one (plaice only). The results showed that hand-stripped milt from these other species, excluding rainbow trout (from which it was possible to obtain urine-free milt), also had markedly high levels of conjugated cortisol (200–1000 ng∙mL−1). Urine of herring and plaice had particularly high levels of conjugated cortisol (ca. 5 μg∙mL−1). Uncontaminated seminal fluid from herring, but not from plaice, also had high levels of conjugated cortisol (ca. 2 μg∙mL−1). Urine and plasma, but not seminal fluid, of herring had elevated levels of conjugated 17α,20β-dihydroxy-4-pregnen-3-one. Urine, but not plasma or seminal fluid, of male plaice had elevated levels of 17α,20α -dihydroxy-4-pregnen-3-one and 3α,17α,21-trihydroxy-5β-pregnan-20-one. It would appear that fish urine is a rich source of conjugated steroids and that care must be taken, when collecting milt for pheromone studies, to avoid urine contamination.

RETINOIC ACID MODULATES RETINAL DEVELOPMENT IN THE JUVENILES OF A TELEOST FISH

1994 ◽  
Vol 193 (1) ◽  
pp. 191-207 ◽  
Author(s):  
H Browman ◽  
C Hawryshyn
Keyword(s):  
Retinoic Acid ◽  
Rainbow Trout ◽  
Photoreceptor Cell ◽  
Normal Development ◽  
Photoreceptor Cells ◽  
Single Class ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Near Ultraviolet ◽  
Retinal Photoreceptor ◽  
All Trans Retinoic Acid

Small (&lt;30 g) juvenile rainbow trout (Oncorhynchus mykiss) possess retinal photoreceptor mechanisms sensitive to light in the near ultraviolet, short (blue), middle (green) and long (red) wavelengths. During normal development, the ultraviolet cone mechanism gradually disappears until, by approximately 60&shy;80 g, individuals are no longer sensitive in the ultraviolet. This shift in spectral sensitivity is associated with the loss of a single class of photoreceptor cells &shy; small accessory corner cones &shy; from the retinal photoreceptor cell mosaic. Treating small (&lt;15 g) rainbow trout with 10(-6) mol l-1 all-trans retinoic acid (20 min exposure by immersion) induced a precocial loss of ultraviolet photosensitivity and an associated change in the retinal photoreceptor cell mosaic only 2 weeks after treatment. These changes were indistinguishable from the events that occur during normal development. Six weeks after exposure to retinoic acid, large (&gt;90 g) rainbow trout, which had lost their ultraviolet cones during normal development, were once again ultraviolet-photosensitive and small accessory corner cones were found in their retinas. These results imply that the ultraviolet-sensitive cones, although lost at one point during development, can reappear at another time during the life history of the same individual. Retinoic acid is involved in these morphogenetic processes.

Growth hormone receptors in the liver and osmoregulatory organs of rainbow trout: characterization and dynamics during adaptation to seawater

1991 ◽  
Vol 130 (3) ◽  
pp. 425-433 ◽  
Author(s):  
T. Sakamoto ◽  
T. Hirano
Keyword(s):  
Growth Hormone ◽  
Rainbow Trout ◽  
Binding Sites ◽  
Chum Salmon ◽  
Hormone Receptors ◽  
Sea Water ◽  
Specific Binding ◽  
Head Kidney ◽  
Scatchard Analysis ◽  
Single Class

ABSTRACT Specific binding sites for chum salmon growth hormone (sGH) were identified in the membranes obtained from tissues of rainbow trout. Specific binding of 125I-labelled sGH (% per mg protein) was found in the liver (37%), ovary (6%), brain (6%), gill (4%), intestine (4%) and posterior body kidney (4%). Specific binding was not significant in head kidney, anterior body kidney, spleen, heart, skeletal muscle or skin. Scatchard analyses demonstrated the presence of a single class of high-affinity low-capacity receptors in the liver, gill, intestine and kidney. The association constants for the membranes from liver, gill, intestine and kidney were of the same order (1 litre/nmol). Chum salmon prolactin did not inhibit the binding of 125I-labelled sGH to receptors in the liver, gill, intestine and kidney. Transfer of rainbow trout from fresh water to 80% seawater evoked a rise in plasma concentration of GH and a significant decrease in the GH binding to the liver membranes after 1 day. Binding in the gill and kidney was not altered significantly. Membranes were treated with 4 mol MgCl2/l to remove bound GH from the receptors, and the results indicated that the reduction in binding in the liver after transfer to sea-water was probably due to receptor occupancy by increased endogenous GH. The occupancy of liver GH-binding sites was maximal 4 days after transfer. Total (MgCl2-treated) binding sites in the liver increased significantly 14 days after transfer. Scatchard analysis indicated that receptors were altered in capacity without changes in binding affinity. Although GH may also directly affect osmoregulatory organs through their GH receptors, the present results indicate the likelihood of at least partial mediation by the liver of the seawater-adapting action of GH in the rainbow trout. Journal of Endocrinology (1991) 130, 425–433

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