Neurotransmission

Recent advances in the study of alcoholism have thrown
light on the involvement of various neurotransmitters in the
phenomenon of alcohol addiction. Various neurotransmitters
have been implicated in alcohol addiction due to their
imbalance in the brain, which could be either due to their
excess activity or inhibition. This review paper aims to
consolidate and to summarize some of the recent papers
which have been published in this regard. The review
paper will give an overview of the neurobiology of alcohol
addiction, followed by detailed reviews of some of the recent
papers published in the context of the genetics of alcohol
addiction. Furthermore, the author hopes that the present
text will be found useful to novices and experts alike in the
field of neurotransmitters in alcoholism.

Neurochemistry and drug addiction. Neurocognitive approach. Cognitive Neuroscience. Research for the Postgraduate Program in Cognitive Sciences of the University of Costa Rica. This research establishes a theoretical basis for the biochemical and neurophysiological bases of behavior and mental phenomena, as well as analyzing the neuropathologies derived from the consumption of toxic substances. Plausible explanations are given for the relationships between toxic and addictive and addictive behaviors, and their neurophysiological and genetic bases. // Neuroquímica y toxicodependencia. Enfoque de neurocognoscitivo.  Neurociencias Cognoscitivas. Investigación para el Programa de Postgrado en Ciencias Cognoscitivas de la Universidad de Costa Rica.  Esta investigación, establece una fundamenta teórica de las bases bioquímicas y neurofisiológicas de la conducta y de los fenómenos mentales, así como analiza las neuropatologías derivadas del consumo de tóxicos. Se plantean explicaciones plausibles de las relaciones entre tóxicos y conductas dependientes y adictivas, y sus bases neurofisiológicas y genéticas. // Rodolfo J. Rodríguez-Rodríguez. E-Mail: rodolfojrr@gmx.com

Although the second-generation or atypical antipsychotic drugs have been breakthrough medicines for the treatment of schizophrenia and other psychotic conditions, cognitive dysfunction and to some extent negative symptoms of the disease continue to be the main cause of poor vocational status of the patients. Thus, the majority of investigational drug development efforts today target these unmet medical needs. This review postulates that the field of schizophrenia research has advanced sufficiently to develop biochemical hypotheses of the etiopathology of the disease and target the same for revolutionary disease modifying therapy. This postulate is based on recent studies that have begun to provide a testable etiopathology model that integrates interactions between genetic vulnerability factors, neurodevelopmental anomalies, and neurotransmitter systems. This review begins with a brief overview of the nosology and etiopathology of schizophrenia and related psychotic disorders to esta...

Recent evidences suggest that glutamatergic dysregulation implicated in neural plasticity and cellular resilience may contribute to the pathophysiology of Major Depressive Disorder (MDD). Riluzole, which exerts its effect by targeting glutamate neurotransmission, has shown antidepressant effect in recent preclinical, observational and open label studies. This study aimed to assess the efficacy and tolerability of riluzole in patients with MDD. Sixty-four inpatients with diagnosis of moderate to severe major depressive disorder participated in a parallel, randomized, controlled trial, and sixty patients underwent 6 weeks treatment with either riluzole (50 mg/bid) plus citalopram (40 mg/day) or placebo plus citalopram (40 mg/day). All participants were inpatients for the whole duration of the study. Patients were assessed using Hamilton depression rating scale (HDRS) at baseline and weeks 2, 4 and 6. The primary outcome measure was to assess the efficacy of riluzole compared to placebo in improving the depressive symptoms. General linear model repeated measures demonstrated significant effect for time _ treatment interaction on HDRS [F (1.86, 107.82) ¼ 8.63, p < 0.001]. Significantly greater improvement was observed in HDRS scores in the riluzole group compared to the placebo group from baseline HDRS score at weeks 2, 4 and 6 (p < 0.001, p ¼ 0.001, p ¼ 0.002, respectively). Significantly greater response with greater speed to treatment was observed in the riluzole group than the placebo group. No serious adverse event occurred. This study showed a favorable safety and efficacy profile in patients with major depressive disorder. Larger controlled studies with longer treatment periods are needed to investigate long term safety, efficacy and optimal dosing.

In Greek, the word “nature” derives from the verb phyō, to come forth, to grow, to become. It is life independent of thought, and non-constructed. Aristotle calls physis “the coming-to-be what it is” (1960: 193a). Nature as physis contains both the movement of emergence and the specific growth, becoming and being, productivity and product. Growth in this context implies that withering and demise belong to it; genesis is always phthora, decay is integral to the act of coming-to-light. In pre-Socratic thought, the human being is seen as part of physis, which contains the human as a whole and in his/her individuality. The focus of the Roman words nasci and natura is, however, on being conceived and being born. Natura now means “native” and “inherent,” but is also defined in terms of the right of disposal, which influenced the formation of the modern term of object (cf. Picht 1998: 90). Nature as the quintessence of objects is nature as the sum of everything that is at our disposal in thought and action.

Stereotaxic injections of pertussis toxin (3-4 micrograms) over the right hippocampus resulted in blockade of long-term potentiation (LTP) induction in the ipsilateral stratum radiatum-CA1 and stratum oriens-CA1 synaptic systems. LTP of intracellularly recorded excitatory postsynaptic potentials was prevented in slices obtained from the hippocampus at 3 and 4 but not 6 days post-toxin injection. Slices taken from the left (contralateral) hippocampus on the same days as above exhibited LTP which was similar to that obtained in control slices from uninjected rats. The post- but not presynaptic actions of adenosine were antagonized at 3, 4 and 6 days post-toxin injection. The observations suggest that the guanosine triphosphate binding proteins involved in LTP induction (GLTP) and those coupled to the postsynaptic adenosine receptors exhibit different turnover times.

Rod and cone photoreceptors possess ribbon synapses that assist in the transmission of graded light responses to second-order bipolar and horizontal cells of the vertebrate retina. Proper functioning of the synapse requires the juxtaposition of presynaptic release sites immediately adjacent to postsynaptic receptors. In this review, we focus on the synaptic, cytoskeletal, and extracellular matrix proteins that help to organize photoreceptor ribbon synapses in the outer plexiform layer. We examine the proteins that foster the clustering of release proteins, calcium channels, and synaptic vesicles in the presynaptic terminals of photoreceptors adjacent to their postsynaptic contacts. Although many proteins interact with one another in the presynaptic terminal and synaptic cleft, these protein–protein interactions do not create a static and immutable structure. Instead, photoreceptor ribbon synapses are remarkably dynamic, exhibiting structural changes on both rapid and slow time scales.