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Showing posts with label Function. Show all posts
Showing posts with label Function. Show all posts

Friday, September 2, 2016

What is the Function of the Hypothalamus?

The hypothalamus is a small area in the center of the brain that has many jobs. It plays an important role in hormone production and helps to stimulate many important processes in the body.

When the hypothalamus is not working properly, it can cause problems in the body leading to many disorders. Though diseases of the hypothalamus are uncommon, it is important to keep it healthy to keep the risk low.

Contents of this article:
  1. What is the hypothalamus?
  2. Hypothalamus disorders
  3. Diet tips for hypothalamus health

The hypothalamus plays a huge role in both the endocrine and nervous systems. Head injuries impacting
the hypothalamus are the most common cause of hypothalamic disease. Diets high in saturated fats can
influence and alter the function of the hypothalamus.

Thursday, May 5, 2016

The mechanisms and functions of spontaneous neurotransmitter release

Fast synaptic communication in the brain requires synchronous vesicle fusion that is evoked by action potential-induced Ca2+ influx. However, synaptic terminals also release neurotransmitters by spontaneous vesicle fusion, which is independent of presynaptic action potentials. A functional role for spontaneous neurotransmitter release events in the regulation of synaptic plasticity and homeostasis, as well as the regulation of certain behaviours, has been reported. In addition, there is evidence that the presynaptic mechanisms underlying spontaneous release of neurotransmitters and their postsynaptic targets are segregated from those of evoked neurotransmission. These findings challenge current assumptions about neuronal signalling and neurotransmission, as they indicate that spontaneous neurotransmission has an autonomous role in interneuronal communication that is distinct from that of evoked release.

Key points
  • Synaptic terminals can release neurotransmitter by spontaneous vesicle fusion that is independent of presynaptic action potentials.
  • The traditional view of spontaneous neurotransmitter release suggests that spontaneous events occur randomly in the absence of stimuli owing to low-probability conformational changes in the vesicle fusion machinery.
  • Recent studies have identified key distinctions between the synaptic vesicle fusion machineries that perform spontaneous versus evoked neurotransmitter release.
  • In mammalian hippocampal synapses and at the Drosophila melanogaster neuromuscular junction, spontaneous and evoked neurotransmitter release events show some spatial segregation and activate distinct populations of postsynaptic receptors.
  • Segregation of spontaneous neurotransmission enables selective neuromodulation that is independent of evoked release.
  • In mammalian hippocampal synapses and at the D. melanogaster neuromuscular junction, spontaneous release events activate specific postsynaptic signal transduction cascades that maintain synaptic efficacy or regulate structural plasticity and synaptic development.
  • Novel strategies that selectively target spontaneous release events are needed to address whether spontaneous release can signal independently during ongoing activity in intact neuronal circuits.
  • Introduction
Introduction
Our current insights into the mechanisms underlying synaptic transmission originate from experiments that were conducted in the 1950s by Bernard Katz and colleagues. A key aspect of these studies was the discovery of spontaneous neurotransmitter release events, which seemed to occur in discrete 'quantal' packets. This fundamental observation enabled the complex and seemingly intractable nature of action potential-evoked neurotransmission to be analyzed and understood on the basis of its unitary components. Although the original work solely relied on electrophysiological analysis, later studies that used electron microscopy provided visual validation of the hypothesis that neurotransmission occurs through fusion of discrete synaptic vesicles that contain neurotransmitters with the presynaptic plasma membrane.


Figure 3: Segregation of spontaneous and evoked neurotransmission.

Sunday, April 10, 2016

Hemoglobin Review

Much of our understanding of human physiology, and of many aspects of pathology, has its antecedents in laboratory and clinical studies of hemoglobin. Over the last century, knowledge of the genetics, functions, and diseases of the hemoglobin proteins has been refined to the molecular level by analyses of their crystallographic structures and by cloning and sequencing of their genes and surrounding DNA. In the last few decades, research has opened up new paradigms for hemoglobin related to processes such as its role in the transport of nitric oxide and the complex developmental control of the α-like and β-like globin gene clusters. It is noteworthy that this recent work has had implications for understanding and treating the prevalent diseases of hemoglobin, especially the use of hydroxyurea to elevate fetal hemoglobin in sickle cell disease. It is likely that current research will also have significant clinical implications, as well as lessons for other aspects of molecular medicine, the origin of which can be largely traced to this research tradition.

Introduction
During the past 60 years, the study of human hemoglobin, probably more than any other molecule, has allowed the birth and maturation of molecular medicine. Laboratory research, using physical, chemical, physiological, and genetic methods, has greatly contributed to, but also built upon, clinical research devoted to studying patients with a large variety of hemoglobin disorders.

Read more: Hemoglobin Review


Source: bloodjournal
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