Epigenetic Mechanisms Mediate Nicotine-Induced Reward and Behaviour in Zebrafish.

Nicotine induces long-term changes in the neural activity of the mesocorticolimbic reward pathway structures. The mechanisms involved in this process have not been fully characterized. The hypothesis discussed here proposed that epigenetic regulation participates in the installation of persistent adaptations and long-lasting synaptic plasticity generated by nicotine action on the mesolimbic dopamine neurons of zebrafish.

P2X7 and A receptor endogenous activation protects against neuronal death caused by CoCl -induced photoreceptor toxicity in the zebrafish retina.

Injured retinas in mammals do not regenerate and heal with loss of function. The adult retina of zebrafish self-repairs after damage by activating cell-intrinsic mechanisms, which are regulated by extrinsic signal interactions. Among relevant regulatory extrinsic systems, purinergic signaling regulates progenitor proliferation during retinogenesis and regeneration and glia proliferation in proliferative retinopathies.

Characterization of proliferative, glial and angiogenic responses after a CoCl -induced injury of photoreceptor cells in the adult zebrafish retina.

The adult zebrafish is considered a useful model for studying mechanisms involved in tissue growth and regeneration. We have characterized cytotoxic damage to the retina of adult zebrafish caused by the injection of cobalt chloride (CoCl ) into the vitreous cavity. The CoCl concentration we used primarily caused injury to photoreceptors.

Injury-induced purinergic signalling molecules upregulate pluripotency gene expression and mitotic activity of progenitor cells in the zebrafish retina.

Damage in fish activates retina repair that restores sight. The purinergic signalling system serves multiple homeostatic functions and has been implicated in cell cycle control of progenitor cells in the developing retina. We examined whether changes in the expression of purinergic molecules were instrumental in the proliferative phase after injury of adult zebrafish retinas with ouabain.

The effect of previous exposure to nicotine on nicotine place preference.

Rationale: Prior exposure to drugs of abuse may increase or decrease the reinforcing effects of the drug in later consumptions. Based on the initial locomotor activity (LA) response to an acute drug administration or to novelty in an open-field arena, animals can be classified as low or high LA responders (LR or HR). Few studies have used this classification with nicotine, and the results are controversial.

The p75 neurotrophin receptor is expressed by adult mouse dentate progenitor cells and regulates neuronal and non-neuronal cell genesis.

Background: The ability to regulate neurogenesis in the adult dentate gyrus will require further identification and characterization of the receptors regulating this process. In vitro and in vivo studies have demonstrated that neurotrophins and the p75 neurotrophin receptor (p75NTR) can promote neurogenesis; therefore we tested the hypothesis that p75NTR is expressed by adult dentate gyrus progenitor cells and is required for their proliferation and differentiation.

Results: In a first series of studies focusing on proliferation, mice received a single BrdU injection and were sacrificed 2, 10 and 48 hours later.

Nicotine-conditioned place preference induced CREB phosphorylation and Fos expression in the adult rat brain.

Rationale: Experimental evidence indicates that nicotine causes long-lasting changes in the brain associated with behavior. Although much has been learned about factors participating in this process, less is known concerning the mechanisms and brain areas involved in nicotine preference.

Objectives: The objective of this study is to examine the participation of brain structures during the development of nicotine-conditioned place preference (CPP).

Cellular processing of cone photoreceptor cyclic GMP-gated ion channels: a role for the S4 structural motif.

We examined cellular protein processing and functional expression of photoreceptor cyclic nucleotide-gated (CNG) ion channels. In a mammalian cell line, wild type bovine cone photoreceptor channel alpha subunits (bCNGA3) convert from an unglycosylated state, at 90 kDa, to two glycosylated states at 93 and 102 kDa as they transit within the cell to their final location at the plasma membrane. Glycosylation per se is not required to yield functional channels, yet it is a milestone that distinguishes sequential steps in channel protein maturation.