The electric sense of mormyrids is often regarded as an adaptation to conditions unfavourable for vision and in these fish it has become the dominant sense for active orientation and communication tasks. With this sense, fish can detect and distinguish the electrical properties of the close environment, measure distance, perceive the 3-D shape of objects… (More)
The present study examined the effect of acute administration of endocannabinoid receptor CB1 ligand ∆-9-tetrahydrocannabinol (THC) on intracellular signalling in the brain and retrieval from two different memory systems in the zebrafish (Danio rerio). First, fish were treated with THC and changes in the phosphorylation level of mitogen-activated protein… (More)
Weakly electric fish can perceive electric properties of objects by monitoring the responses of their epidermal electroreceptors (mormyromasts) to their own electric organ discharges (EOD), a process known as active electrolocation. Mormyrid fish can distinguish capacitative from resistive properties of objects. It is mainly animate objects that possess… (More)
BACKGROUND Electric fish navigate and explore their dark and turbid environment with a specialised electric sense. This active electrolocation involves the generation and perception of an electric signal and fish have proven to be useful model systems for the investigation of sensory-motor interactions. A well studied example is the elephantnose fish,… (More)
Introduction Since the early 1950s it is known that so-called weakly electric fish generate electrical signals with a special electric organ in their tail (Lissmann, 1951). During each electric organ discharge (EOD) an electric field builds up around the fish (Lissmann, 1958). The animal perceives its own electric emissions with epidermal electroreceptor… (More)
I hereby declare that I prepared this thesis entitled: " Neuropeptides in stress reactivity: Role of enkephalin in stress response " by myself except where otherwise stated. All text passages that are literally taken from published or unpublished papers are indicated as such. knockout male mice are resistant to chronic mild stress.
In order to determine the influence of environmental interventions, medical substances, drugs, or diseases on an animal, it is a common to observe the behaviour of the animal in the open field or in other environments. Changes in animal behaviour can be the first indicators for an influence of a substance or an intervention on the organism and certain kinds… (More)