Search results for "DOPAMINERGIC"
showing 10 items of 200 documents
Syntheses of dopaminergic 1-cyclohexylmethyl-7,8-dioxygenated tetrahydroisoquinolines by selective heterogeneous tandem hydrogenation
2002
Abstract We describe the preparation in a ‘one-pot’ sequence 1-cyclohexylmethyl 7,8-dioxygenated tetrahydroisoquinoline, substituted and unsubstituted in the C ring by application of the Photo–Fries transposition, followed by a tandem reduction–cyclization and further reduction. Indeed, we have accomplished for the first time regioselective hydrogenation of the benzylic ring of the tetrahydroisoquinoline systems. All 1-cyclohexylmethyl THIQ synthesized were able to displace D2 dopamine receptor from its specific binding site in rat striatal membranes, while the N-methylated derivatives showed also affinity for D1 dopamine receptors.
Influence of ventral tegmental area (A10 region) on flight behaviour elicited by hypothalamic stimulation in the cat.
1993
The influence of the ventral tegmental area (VTA) (dopaminergic A10 group neurons) on flight behaviour, induced by hypothalamic stimulation, was studied in the cat. Co-stimulation of hypothalamus and VTA (ipsi- or contralateral) induced an increase of the flight latency. Slow-motion analysis of flight behaviour showed that this increase was due to the augmentation of the fixation latency (FL) whereas the upright latency (UL) was not modified. Sulpiride injection (50 mg/kg i.p.) provoked the disappearance of VTA effect without affecting the basal behavioural sequence. The results show that DA A10 group neurons increase the attentive component of the flight reaction, suggesting a possible inf…
Naltrexone antagonizes acetaldehyde-induced increments in dopamine neurons activity
2014
Abstract Acetaldehyde is the main metabolite of ethanol ingested through alcoholic beverages. Traditionally considered aversive is presently being viewed as an activating agent of the mesolimbic dopamine system but underlying mechanisms are only partially known. Here we show that acetaldehyde-induced increase in firing rate, burst firing and spikes/burst of antidromically-identified ventro-tegmental area Nucleus Accumbens-projecting neurons are abolished by pretreatment with the opiate unselective antagonist naltrexone (1mg/kg/ip). Similar effects are obtained after administration of naloxone (0.1mg/kg/iv). These results indicate: 1) endogenous opiate system(s) participate in acetaldehyde-i…
Ankk1 Loss of Function Disrupts Dopaminergic Pathways in Zebrafish
2022
Ankyrin repeat and kinase domain containing 1 (ANKK1) is a member of the receptor-interacting protein serine/threonine kinase family, known to be involved in cell proliferation, differentiation and activation of transcription factors. Genetic variation within the ANKK1 locus is suggested to play a role in vulnerability to addictions. However, ANKK1 mechanism of action is still poorly understood. It has been suggested that ANKK1 may affect the development and/or functioning of dopaminergic pathways. To test this hypothesis, we generated a CRISPR-Cas9 loss of function ankk1 zebrafish line causing a 27 bp insertion that disrupts the ankk1 sequence introducing an early stop codon. We found that…
Inhibitory effect of A10 dopaminergic neurons of the ventral tegmental area on the orienting response evoked by acoustic stimulation in the cat.
1998
Abstract The effect of bilateral electric stimulation of A10 dopaminergic neurons of the ventral tegmental area (80–300 μA, 20–50 Hz, 0.1–0.5 ms, 2 s duration) on latency and duration of the orienting response, evoked by acoustic stimuli (4500–8000 Hz, 2 s), was studied in the cat. A10 neuron stimulation, simultaneous with the acoustic one, was performed with threshold parameters inducing minimal behavioral signs (head searching movement, sniffing, increase in alertness). By means of a videoanalysis system, a statistically significant increase, both of latency and duration of the response, was observed. The possible role of dopamine was studied administrating sulpiride (20 mg/kg IP), a dopa…
Neuronal and neuroendocrine mechanisms of social rank and stress coping in teleost fish
2015
Fights for social dominance are stressful and results in an activation of the brain serotonergic system. Subordinate animals in an established dominance hierarchy are characterized by a chronic elevation of brain serotonergic activity, an effect that seems to mediate the behavioural inhibition observed in these animals. By contrast, social dominance has been associated with elevated dopaminergic activity, and dopamine (DA) has behavioural effects to some extent opposing those of serotonin (5HT). In addition to effects of the social environment, brain monoaminergic functions are controlled by genetic factors. For instance, zebrafish (Danio rerio) classified as bold, showing a propensity for …
Nuevos fármacos inspirados en Annonáceas
2014
Los metabolitos secundarios activos (MSA) juegan un papel importante en el descubrimiento de nuevos medicamentos. Moléculas naturales con esqueletos complejos, tales como las estatinas aisladas de Aspergillus terreus, o las acetogeninas específicas de la familia Annonaceae, no hubieran podido ser inventadas en ningún laboratorio. Los MSA aislados en Annonaceae, especialmente las acetogeninas y los alcaloides isoquinoleínicos, pueden ser considerados como fuente constante de inspiración para químicos, farmacólogos y para todos los investigadores interesados en el descubrimiento de una nueva familia de medicamentos. Active secondary metabolites (ASM) play a highly significant role in the drug…
Focus on the Small GTPase Rab1: A Key Player in the Pathogenesis of Parkinson’s Disease
2021
Parkinson’s disease (PD) is the second most frequent neurodegenerative disease. It is characterized by the loss of dopaminergic neurons in the substantia nigra and the formation of large aggregates in the survival neurons called Lewy bodies, which mainly contain α-synuclein (α-syn). The cause of cell death is not known but could be due to mitochondrial dysfunction, protein homeostasis failure, and alterations in the secretory/endolysosomal/autophagic pathways. Survival nigral neurons overexpress the small GTPase Rab1. This protein is considered a housekeeping Rab that is necessary to support the secretory pathway, the maintenance of the Golgi complex structure, and the regulation of macroau…
Evolution of vertebrate survival circuits
2018
Evolution selects those adaptive features that increase reproductive probabilities and facilitate survival. Analysing the brain circuits mediating risk-avoidance (e.g. defense) and those allowing reward-seeking (motivated) behaviours in different vertebrates leads to several main conclusions. First, circuits mediating risk-avoidance are similar in all studied vertebrates, where they include amygdala homologues located in the posterior half of the cerebral hemispheres, in close relationship with the chemosensory systems. Second, in all vertebrates, reward-seeking behaviours involve the activity of tegmento-striatal dopaminergic pathways, plus other inputs to the ventral striatum, including a…
Serotonin–dopamine interaction: an overview
2008
Central serotonergic and dopaminergic systems play a critical role in the regulation of normal and abnormal behaviours. Moreover, recent evidence suggests that the dysfunction of dopamine (DA) and serotonin (5-hydroxytriptamine, 5-HT) neurotransmission might underlie the pathophysiology of neuropsychiatric disorders, including depression, schizophrenia, attention deficit hyperactivity disorders, drug abuse, Gilles de la Tourette's syndrome and Parkinson's disease.