The mechanisms and sites of action of epibatidine-induced antinociception and side effects are poorly understood. The present study tested the hypothesis that the serotonergic dorsal raphe nucleus is a site of action of epibatidine. Behavioral responses of rats to hindpaw formalin injection were compared after direct administration of epibatidine into the dorsal raphe and after subcutaneous adm...

The norepinephrine transporter (NET) is a site of action for tricyclic antidepressant drugs and for drugs of abuse such as amphetamine and cocaine. In this study, the binding of [3H]nisoxetine to NETs in the noradrenergic cell group, the locus coeruleus, and the serotonergic cell groups, the dorsal raphe nuclei, was measured autoradiographically in postmortem human brain. [3H]nisoxetine binding...

Recombinant mouse tryptophan hydroxylase (TPH) was expressed in Escherichia coli, using a bacterial expression vector and has been purified to homogeneity by sonication followed by Sepharose 4B column chromatography and native slab gel electrophoresis. This purified enzymatically active TPH protein was used for production of a specific antiserum. This antiserum identified the predicted TPH band...

During waking behavior, animals adapt their state of arousal in response to environmental pressures. Sensory processing is regulated in aroused states, and several lines of evidence imply that this is mediated at least partly by the serotonergic system. However, there is little information directly showing that serotonergic function is required for state-dependent modulation of sensory processi...

Cataplexy, a symptom associated with narcolepsy, represents a unique dissociation of behavioural states. During cataplectic attacks, awareness of the environment is maintained, as in waking, but muscle tone is lost, as in REM sleep. We have previously reported that, in the narcoleptic dog, noradrenergic cells of the locus coeruleus cease discharge during cataplexy. In the current study, we repo...

The importance of the lateral habenula-dorsal raphe pathway in the control of in vivo [3H]serotonin release in the cat basal ganglia was examined using the push-pull cannula technique and an isotopic method for the estimation of [3H]serotonin continuously formed from [3H]tryptophan. [3H]Serotonin was measured in both caudate nuclei and substantiae nigra and, in some cases, in the dorsal raphe. ...

BACKGROUND AND PURPOSE Tryptophan hydroxylase activity was assayed in cell-free extracts of rat brain base arteries as marker of a serotonergic innervation. METHODS Estimation of the enzymatic activity was made in untreated male Sprague-Dawley rats (n = 53) and in those who underwent destruction of the dorsal and median raphe nuclei (n = 10). RESULTS Tryptophan hydroxylase activity was meas...

introduction: the role of serotonergic fibers in avoidance learning is controversial. involvement of the dorsal raphe nucleus (drn), the main source of hippocampal projecting serotonergic fibers in acquisition, consolidation and retrieval of passive avoidance (pa) learning, was investigated by functional suppression of this area. materials and methods: drn functional inactivation was done by li...

The recent introduction ofa number offluorescent retrograde axonal tracers that have different emission spectra (1,2,9,10,25,26) has permitted the investigation of possible collateral projections of senotonengic neurons. Extensive collateralization from single neurons in the raphe nuclei was expected given the widespread distribution ofserotonergic nerve terminals in the central nervous system ...

The effects of MDMA (3,4-methylenedioxymethamphetamine) on the activity of serotonin (5-HT)-containing dorsal raphe neurons were characterized using extracellular single-unit recording and microdialysis techniques in the in vitro midbrain slice preparation. Addition of (+)-MDMA, (-)-MDMA or p-chloroamphetamine (PCA) to the superfusate (final concentration 3-100 microM) produced a concentration-...