Thyroid hormones transiently increase during parr-smolt transformation in coho salmon, Oncorhynchus kisutch, and are believed to trigger morphological, physiological, behavioural, and neural changes. The effectiveness of propylthiouracil (PTU) to induce hypothyroidism in smolting coho salmon was determined by immersing coho salmon, Oncorhynchus kisutch, in 30 mg 1-1 PTU from May 1, two weeks prior

Free plasma thyroxine (FT4) levels were measured in coho salmon, Oncorhynchus kisutch, during parr-smolt transformation (smoltification) using an equilibrium dialysis system followed by a radioimmunoassay. The FT4 data were correlated to total plasma thyroxine (TT4), triiodothyronine (TT3), and growth hormone (GH). Plasma samples were taken weekly from early April to late May, when the salmon wher

1. During early ontogeny, the serotonergic neurons in the brain stem of the three-spined stickleback shows a temporal and spatial developmental pattern that closely resembles that of amniotes. 2. However, in the adult fish, only the midline nuclei of the rostral group (dorsal and median raphe nuclei) and the dorsal lateral tegmental nucleus are consistently serotonin-immunoreactive (5-HTir), where

The organization of the serotonergic cell groups in the brainstem of fishes and amphibians has received relatively little attention. It has been generally assumed that they are little differentiated and constitute a median cell column throughout the brainstem, and that laterally migrated serotonergic cell groups are largely lacking. In the present study we present evidence to the contrary. By the

The inhibitory neurotransmitter γ-aminobutyric acid (GABA) is known to exert various neurotrophic actions in the developing nervous system, but little is known about its distribution in the central nervous system during early development. We have studied the development of GABA-immunoreactive (GABAir) neurons during embryogenesis of a teleost fish, the three-spined stickleback. As early as 51 h po

The ontogenetic development of serotoninergic neurons in the brain of the stickleback was investigated with the indirect immunocytochemical peroxidase-antiperoxidase technique, using a specific antibody to serotonin (5-hydroxytryptamine, 5-HT). Formation of neuronal populations takes place during embryonic development. By 80 h after fertilization, the first 5-HT perikarya have appeared in the vent

In the coho salmon there is a transient increase in total brain concentrations of serotonin during smolt transformation which occurs midlife, just before down-stream migration to the ocean. There is also a gradual age-related increase in total brain serotonin concentrations. These increases may be due to reorganization of the central serotonergic system, changes in serotonin turnover, or both. The

The development of catecholaminergic neuronal systems in the brain of a teleost, the three-spined stickleback, was studied through embryonic to early larval stages by immunocytochemistry using specific antibodies against dopamine, tyrosine hydroxylase and dopamine β-hydroxylase. By analysing the spatiotemporal patterns of development for the catecholaminergic nuclei, possible homologies with nucle

Antisera against a variety of substances have been found to produce an identical immunoreaction in the developing olfactory system of a teleost, the three-spined stickleback (Gasterosteus aculeatus). The label is localized in the olfactory placode, the olfactory nerve and those parts of the secondary olfactory tracts which constitute the dorsal descending fascicles and the ventral descending fiber

The expression of the engrailed homeobox gene during trout embryogenesis has been examined using immunohistochemistry and the monoclonal antibody 'Mab 4D9'. Engrailed has been suggested to play an important role during development by controlling position-specific characteristics in the CNS of the early embryo. In the present study we have analyzed the expression of engrailed at 5 stages of embryon

The European Spallation Source, now under construction in Lund, Sweden, aims to be the world's most powerful pulsed neutron scattering facility. Driving the neutron source is a 5 MW superconducting proton linear accelerator operating at 4 percent beam duty factor and 14 Hz repetition rate. Nineteen partner institutions from across Europe are working with the Accelerator Division in Lund to design

The localization of gamma‐aminobutyric acid (GABA)‐ and L‐glutamate 1 carboxy‐lyase (GAD)‐immunoreactive neurons was compared in the skate, frog, pigeon, chicken, rabbit, and man. Horizontal cells show both GABA and GAD immunoreactivity in the skate, frog, and bird. Certain amacrine cells show GABA and GAD immunoreactivity in all species. The distribution of GABA‐ and GAD‐immunoreactive cell bodie

The retinofugal projections in the eel were studied by use of the cobalt-filling technique. The optic tract projects contralaterally to the hypothalamic optic nucleus, the anterior periventricular nucleus, the lateral geniculate nucleus, the dorsomedial optic nucleus, four pretectal recipient areas, the optic tectum, and the tegmentum. Small ipsilateral projections were demonstrated in the hypotha

Putative GABAergic elements in the retina of the Atlantic salmon have been identified by immunohistochemistry, utilising polyclonal antisera against γ-aminobutyric acid (GABA) and the GABA transporter GAT-1. Cell types immunoreactive (ir) for GABA comprise horizontal cells, amacrine cells, displaced amacrine cells in the ganglion cell layer, displaced amacrine cells in the inner plexiform layer (i

The neuroanatomical organization of neurons projecting to the pituitary and the origin of pituitary dopamine and nonapeptides were investigated in the brain of the Atlantic salmon (Salmo salar). Carbocyanine tract tracing in combination with tyrosine hydroxylase, arginine vasotocin and isotocin immunocytochemistry for double labelling revealed a previously unknown organization of hypophysiotrophic

The distribution of olfactory fibers in the brain of the three‐spined stickleback was visualized by means of immunohistochemistry. The labeling of the olfactory fibers was produced by serum containing antibodies against somatostatin‐14. Olfactory fibers were observed entering the olfactory bulbs, where they terminated in the glomerular layer or collected into fascicles that coursed through the bul

The olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius) has been studied with a conventional histochemical and a novel immunological staining technique. In both species, the sensory epithelium is arranged in folds separated by non-sensory epithelial tissue. In the nine-spined stickleback, intrinsic folds consisting of

The distribution of putative cholinergic neurons in the brain of a cyprinid teleost was investigated by immunocytochemistry, with well‐characterized polyclonal antibodies to porcine choline acetyltransferase (ChAT), correlated with acetylcholinesterase (AChE) histochemistry. AChE‐positive neurons were more numerous than GhAT‐immunoreactive (ChAT‐IR) neurons. Regions with ChAT‐IR neurons generally

By use of antibodies against serotonin, a discrete subnucleus of putatively serotoninergic neurons was observed in the dorsal subdivision of the left habenular nucleus in the brain of the coho salmon. The subnucleus was observed in salmon of different life-stages: in fingerlings, during smolt transformation, after smolt transformation (in seawater), and after spawning. This finding further emphasi