scholarly journals Sensory Processing at Ribbon Synapses in the Retina and the Cochlea

2020 ◽  
Vol 100 (1) ◽  
pp. 103-144 ◽  
Author(s):  
Tobias Moser ◽  
Chad P. Grabner ◽  
Frank Schmitz
Keyword(s):  
Sensory Processing ◽  
Sensory Information ◽  
Structure And Function ◽  
Current Understanding ◽  
Anatomy And Physiology ◽  
Ribbon Synapses ◽  
Signaling Mechanisms ◽  
Molecular Anatomy ◽  
Key Aspects ◽  
And Function

In recent years, sensory neuroscientists have made major efforts to dissect the structure and function of ribbon synapses which process sensory information in the eye and ear. This review aims to summarize our current understanding of two key aspects of ribbon synapses: 1) their mechanisms of exocytosis and endocytosis and 2) their molecular anatomy and physiology. Our comparison of ribbon synapses in the cochlea and the retina reveals convergent signaling mechanisms, as well as divergent strategies in different sensory systems.

Neurologic Emergencies

2019 ◽  
pp. 125-136
Author(s):  
Ross P. Martini ◽  
Ines P. Koerner
Keyword(s):  
Status Epilepticus ◽  
Intracranial Pressure ◽  
Structure And Function ◽  
Neurosurgical Procedures ◽  
Transition Of Care ◽  
Comatose Patient ◽  
Neurologic Emergencies ◽  
Brain Structure And Function ◽  
Key Aspects ◽  
And Function

The primary goal of the neuroanaesthetist and neurointensivist is to preserve brain structure and function, especially in the setting of neurologic insults. Neurologic emergencies can also develop peri-operatively in patients undergoing non-neurosurgical procedures, which the general anaesthetist should be prepared to manage. This chapter on neurologic emergencies discusses herniation syndromes (including pathophysiology of intracranial hypertension, symptoms of herniation, and therapies to reduce intracranial pressure and reverse herniation). It also covers coma (including differential diagnoses of postoperative coma, clinical evaluation of the comatose patient, CT imaging, advanced tests, and directed therapies). Finally, it discusses key aspects of ischaemic stroke, status epilepticus, and transition of care.

Structure and Function of the Plant Alternative Oxidase: Its Putative Role in the Oxygen Defence Mechanism

1997 ◽  
Vol 17 (3) ◽  
pp. 319-333 ◽  
Author(s):  
Anneke M. Wagner ◽  
Anthony L. Moore
Keyword(s):  
Oxidative Stress ◽  
Alternative Oxidase ◽  
Structure And Function ◽  
Current Understanding ◽  
Defence Mechanism ◽  
Putative Role ◽  
And Function

Current understanding of the structure and function of the plant alternative oxidase is reviewed. In particular, the role of the oxidase in the protection of tissues against oxidative stress is developed.

scholarly journals Molecular Assembly and Structural Plasticity of Sensory Ribbon Synapses—A Presynaptic Perspective

2020 ◽  
Vol 21 (22) ◽  
pp. 8758
Author(s):  
Roos Anouk Voorn ◽  
Christian Vogl
Keyword(s):  
Spiral Ganglion ◽  
Structural Plasticity ◽  
Molecular Assembly ◽  
Transport Pathways ◽  
Temporal Precision ◽  
Ribbon Synapses ◽  
Retinal Photoreceptors ◽  
Molecular Anatomy ◽  
Ganglion Neurons ◽  
And Function

In the mammalian cochlea, specialized ribbon-type synapses between sensory inner hair cells (IHCs) and postsynaptic spiral ganglion neurons ensure the temporal precision and indefatigability of synaptic sound encoding. These high-through-put synapses are presynaptically characterized by an electron-dense projection—the synaptic ribbon—which provides structural scaffolding and tethers a large pool of synaptic vesicles. While advances have been made in recent years in deciphering the molecular anatomy and function of these specialized active zones, the developmental assembly of this presynaptic interaction hub remains largely elusive. In this review, we discuss the dynamic nature of IHC (pre-) synaptogenesis and highlight molecular key players as well as the transport pathways underlying this process. Since developmental assembly appears to be a highly dynamic process, we further ask if this structural plasticity might be maintained into adulthood, how this may influence the functional properties of a given IHC synapse and how such plasticity could be regulated on the molecular level. To do so, we take a closer look at other ribbon-bearing systems, such as retinal photoreceptors and pinealocytes and aim to infer conserved mechanisms that may mediate these phenomena.

Endogenous ion channel complexes: the NMDA receptor

2011 ◽  
Vol 39 (3) ◽  
pp. 707-718 ◽  
Author(s):  
René A.W. Frank
Keyword(s):  
Nmda Receptor ◽  
Ion Channel ◽  
Present Article ◽  
Neuronal Excitability ◽  
Structure And Function ◽  
Current Understanding ◽  
Ionotropic Receptors ◽  
Receptor Complexes ◽  
Aspartate Receptor ◽  
And Function

Ionotropic receptors, including the NMDAR (N-methyl-D-aspartate receptor) mediate fast neurotransmission, neurodevelopment, neuronal excitability and learning. In the present article, the structure and function of the NMDAR is reviewed with the aim to condense our current understanding and highlight frontiers where important questions regarding the biology of this receptor remain unanswered. In the second part of the present review, new biochemical and genetic approaches for the investigation of ion channel receptor complexes will be discussed.

scholarly journals Cnr2 Is Important for Ribbon Synapse Maturation and Function in Hair Cells and Photoreceptors

2021 ◽  
Vol 14 ◽  
Author(s):  
Luis Colón-Cruz ◽  
Roberto Rodriguez-Morales ◽  
Alexis Santana-Cruz ◽  
Juan Cantres-Velez ◽  
Aranza Torrado-Tapias ◽  
...  
Keyword(s):  
Hair Cells ◽  
Cannabinoid Receptor ◽  
Sensory Information ◽  
Endocannabinoid System ◽  
Cannabinoid Receptor 2 ◽  
Ribbon Synapses ◽  
Sensory Epithelia ◽  
Synapse Maturation ◽  
And Function

The role of the cannabinoid receptor 2 (CNR2) is still poorly described in sensory epithelia. We found strong cnr2 expression in hair cells (HCs) of the inner ear and the lateral line (LL), a superficial sensory structure in fish. Next, we demonstrated that sensory synapses in HCs were severely perturbed in larvae lacking cnr2. Appearance and distribution of presynaptic ribbons and calcium channels (Cav1.3) were profoundly altered in mutant animals. Clustering of membrane-associated guanylate kinase (MAGUK) in post-synaptic densities (PSDs) was also heavily affected, suggesting a role for cnr2 for maintaining the sensory synapse. Furthermore, vesicular trafficking in HCs was strongly perturbed suggesting a retrograde action of the endocannabinoid system (ECs) via cnr2 that was modulating HC mechanotransduction. We found similar perturbations in retinal ribbon synapses. Finally, we showed that larval swimming behaviors after sound and light stimulations were significantly different in mutant animals. Thus, we propose that cnr2 is critical for the processing of sensory information in the developing larva.

scholarly journals Die brein soos beskou deur die Grieke en Romeine

2015 ◽  
Vol 34 (1) ◽  
Author(s):  
Francois P. Retief ◽  
Louise Cilliers
Keyword(s):  
Brain Function ◽  
Essential Role ◽  
Structure And Function ◽  
Ancient Egypt ◽  
Human Anatomy ◽  
Anatomy And Physiology ◽  
Human Anatomy And Physiology ◽  
And Function ◽  
Remarkable Advance ◽  
The Brain

In Ancient Egypt mummification was associated with extensive organ resection, but the brain was removed through a hole cut in the ethnocide bone. It was thus not observed as an organ. Greek writers of the 6th and 5th centuries BC originally said the brain was the seat of intelligence, the organ of sensory perception and partially the origin of sperm. The substance pneuma, originating from fresh air, played an essential role in brain function. Hippocrates initially described the brain as a double organ, covered by meninges and responsible for perception. Contemporaries like Plato, Aristotle and Diocles confirmed the findings though the latter two considered the heart to be the centre of intelligence. During the late 4th century BC, with the onset of the Hellenistic era of medicine, dissection of the human body was temporarily allowed at the medical school of Alexandria, and this led to a remarkable advance in the understanding of human anatomy and physiology under Herophilus and Erasistratus. Their excellent descriptions of the structure and function of the brain was only matched and surpassed by Galen in the 2nd century AD.

Anatomy and physiology of the gastrointestinal tract

2021 ◽  
pp. 1-16
Author(s):  
Jennie Burch ◽  
Brigitte Collins
Keyword(s):  
Gastrointestinal Tract ◽  
Gall Bladder ◽  
Abdominal Cavity ◽  
Structure And Function ◽  
Pelvic Cavity ◽  
Gi Tract ◽  
Waste Products ◽  
Anatomy And Physiology ◽  
And Function

The anatomy and physiology of the gastrointestinal (GI) tract chapter provides information on the parts, structure, and function of the gut. The hollow tube of the gastrointestinal tract begins at the mouth and ends at the anus. The GI tract in part lies within the abdominal cavity and the pelvic cavity. There are also the accessory organs of the liver, pancreas, and gall bladder. The nerves, hormones, secretions, and blood supply to the gut are also explored. The role of the GI tract is to ingest food and fluids. These are digested through mechanical and chemical means such as chewing. The nutrients are then absorbed, predominantly in the ileum. Waste products are finally eliminated via the anus.

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