Effects of EMF emissions from undersea electric cables on coral reef fish.

The objective of this study was to determine if electromagnetic field (EMF) emissions from undersea power cables impacted local marine life, with an emphasis on coral reef fish. The work was done at the South Florida Ocean Measurement Facility of Naval Surface Warfare Center in Broward County, Florida, which has a range of active undersea detection and data transmission cables. EMF emissions from a selected cable were created during non-destructive visual fish surveys on SCUBA.

Promnestic effects of intranasally applied pregnenolone in rats.

The neurosteroid pregnenolone (PREG) has been shown to have memory-enhancing and anti-depressant action. The present study addresses the question of whether intranasally applied pregnenolone (IN-PREG) also has promnestic properties in the rat. We examined the effects of IN-PREG at doses of 0.

Time-dependent bidirectional effects of chronic caffeine on functional recovery of the dorsal light reflex after hemilabyrinthectomy in the goldfish Carassius auratus.

Caffeine works through a variety of complex mechanisms to exert an often bidirectional set of functional and structural neurological changes in vertebrates. We investigated the effects of chronic caffeine exposure on functional recovery of the dorsal light reflex (DLR) in hemilabyrinthectomized common goldfish, Carassius auratus. In this lesion model, the unilateral removal of the vestibular organs results in a temporary loss of gravitationally modulated postural control which is quantifiable via the DLR.

Active avoidance learning in zebrafish (Danio rerio)--the role of sensory modality and inter-stimulus interval.

The zebrafish (Danio rerio) promises to meet the growing need of a high throughput model in the fields of gerontological and neurobehavioral research by possessing highly conserved anatomy and physiology with vertebrates, while having low maintenance costs. Here we further explore the conditions of active avoidance learning in zebrafish. Two pairs of distinct aversive conditioning experiments using shuttle boxes were designed to compare the effects of sensory modality and conditioned-unconditioned stimulus interval (CS-US interval) upon memory formation and retention.

Depth-variable settlement patterns and predation influence on newly settled reef fishes (Haemulon spp., Haemulidae).

During early demersal ontogeny, many marine fishes display complex habitat-use patterns. Grunts of the speciose genus Haemulon are among the most abundant fishes on western North Atlantic coral reefs, with most species settling to shallow habitats (≤12 m). To gain understanding into cross-shelf distributional patterns exhibited by newly settled stages of grunts (<2 cm total length), we examined: 1) depth-specific distributions of congeners at settlement among sites at 8 m, 12 m, and 21 m, and 2) depth-variable predation pressure on newly settled individuals (species pooled).

Development of embryonic gill vasculature in the yellow stingray, Urobatis jamaicensis.

Corrosion casting was utilized to examine the development of gill vasculature in embryonic yellow stingrays, Urobatis jamaicensis (formerly Urolophus jamaicensis). The most marked changes in vascular configuration of the gills occur in the earliest castable stages of gestation. These changes included development of afferent external gill filament vessels and progression from paired dorsal aortae to a single fused dorsal aorta.

A unique vascular configuration among the efferent branchial arteries and splanchnic arteries in the yellow stingray, Urobatis jamaicensis.

With light and scanning electron microscopy of vascular corrosion casts, we have observed in Urobatis jamaicensis that the fourth epibranchial arteries do not merge completely with the dorsal aorta. Instead they form a brief anastomosis with a short vessel projecting ventrally from the dorsal aorta and maintain their integrity as separately distinct vessels. Posterior to the anastomosis, the right epibranchial becomes the celiac trunk and left epibranchial becomes the anterior mesenteric artery/posterior intestinal artery.

Recent region-wide declines in Caribbean reef fish abundance.

Profound ecological changes are occurring on coral reefs throughout the tropics, with marked coral cover losses and concomitant algal increases, particularly in the Caribbean region. Historical declines in the abundance of large Caribbean reef fishes likely reflect centuries of overexploitation. However, effects of drastic recent degradation of reef habitats on reef fish assemblages have yet to be established.

Changes in motoric, exploratory and emotional behaviours and neuronal acetylcholine content and 5-HT turnover in histidine decarboxylase-KO mice.

Histamine has been implicated, inter alia, in mechanisms underlying arousal, exploratory behaviour and emotionality. Here, we investigated behavioural and neurochemical parameters related to these concepts, including open-field activity, rotarod performance and anxiety, as well as brain acetylcholine and 5-HT concentrations of mice deficient for the histidine decarboxylase (HDC) gene. These mice are unable to synthesize histamine from its precursor histidine.

Histidine-decarboxylase knockout mice show deficient nonreinforced episodic object memory, improved negatively reinforced water-maze performance, and increased neo- and ventro-striatal dopamine turnover.

The brain's histaminergic system has been implicated in hippocampal synaptic plasticity, learning, and memory, as well as brain reward and reinforcement. Our past pharmacological and lesion studies indicated that the brain's histamine system exerts inhibitory effects on the brain's reinforcement respective reward system reciprocal to mesolimbic dopamine systems, thereby modulating learning and memory performance. Given the close functional relationship between brain reinforcement and memory processes, the total disruption of brain histamine synthesis via genetic disruption of its synthesizing enzyme, histidine decarboxylase (HDC), in the mouse might have differential effects on learning dependent on the task-inherent reinforcement contingencies.

Circadian variation of brain histamine in goldfish.

Teleosts may make an excellent model to study brain histamine function. Fishes are phylogenetically closer to the basic vertebrate blueprint than higher vertebrates. They appear to have a simpler histaminergic system in terms of central nervous system distribution and, contrary to higher vertebrates, brain histamine appears to be strictly neuronal.

ACTH4-10, substance P, and dizolcipine (MK-801) accelerate functional recovery after hemilabyrinthectomy in goldfish.

In this study, we evaluated the goldfish model of hemilabyrinthectomy for investigating potential recovery-promoting drugs. In this lesion model, the unilateral removal of the labyrinth induces a postural imbalance in response to light (Dorsal Light Reflex), from which the animals can recover over time. The behavioral effects of two neuropeptides were tested--namely, of substance P and ACTH4-10, both of which are known to promote functional recovery in several other lesion models.

Post-trial administration of H1 histamine receptor blocker improves appetitive reversal learning and memory in goldfish, Carassius auratus.

Based on the hypothesis that neuronal histamine exerts an inhibitory influence on learning and reinforcement, goldfish were tested for post-trial effects of the H1 receptor blocker chlorpheniramine (CPA) on learning the location of a food source in one of two compartments, one black the other white, with a feeder located in each compartment. Testing was carried out over 6 days. On the training day a food pellet was placed into the feeder of one of the compartments.

Ultrastructural analysis of folliculogenesis in the ovary of the yellow spotted stingray, Urolophus jamaicensis.

The ovary of the yellow spotted ray, Urolophus jamaicensis, is embedded in the epigonal gland, a lymphomyeloid organ. The covering of the ovary is composed of a germinal epithelium that is cuboidal and dome-shaped with microvilli. Adjacent cells have elaborate intercellular folds that create dilated intercellular spaces.

Conditioned place-preference analysis in the goldfish with the H1 histamine antagonist chlorpheniramine.

The aim of this study was to investigate whether the histamine H1-receptor blocker, chlorpheniramine (CPA), has a reinforcing effect in goldfish. We used a place-preference procedure in an aquarium with two chambers colored black and white. On day 1, the animals were placed in the test chamber for 10 min for habituation.

Metal redistribution in largemouth bass (Micropterus salmoides) in response to restrainment stress and dietary cadmium: role of metallothionein and other metal-binding proteins.

1. Fish stressed by restrainment displayed elevated serum cortisol, copper and zinc levels; dietary cadmium had no effect. 2.

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish, Medaka, Oryzias latipes.

Medaka were maintained on a 16:8 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule.

Feeding time differentially affects fattening and growth of channel catfish.

Channel catfish (Ictalurus punctatus) were held on a 12-h light, 12-h dark photoperiod (light onset 0600 h) and fed a nonpurified diet daily at either 0730 or 1600 h or a half ration at both of these times of day. The feeding time conducive to total growth (0730 h) differed from that conducive to fattening (1600 h). Fish fed a half ration at both times of day had body weights similar to those fed a single early meal but also had high abdominal fat weights similar to those fed a single late meal.