Explore chapters and articles related to this topic
Traditional Linear Accelerators
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
One property of ion pumps is ideal for their use in linacs. Since the molecular ionisation rate depends linearly on the density of gas molecules (i.e. the pressure), the ion current can be used as a reliable monitor of the pressure in the evacuated system.
The Cell Membrane in the Steady State
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Similar to the Na+-K+ pump is the plasma membrane Ca2+-ATPase (PMCA) that helps maintain a low intracellular Ca2+ concentration in the resting state by pumping Ca2+ outward against a large electrochemical potential gradient. Ion pumps are an example of ion transporters, which transport ions across plasma membranes and membranes of cell organelles. Other types of ion transporters are uniporters and cotransporters that will be discussed in the following section.
Electrophysiological Recording of a Gain-of-Function Polycystin-2 Channel with a Two-Electrode Voltage Clamp
Published in Jinghua Hu, Yong Yu, Polycystic Kidney Disease, 2019
Courtney Ng, Zhifei Wang, Bin Li, Yong Yu
The activity of ion channels and ion pumps, which enables the transport of ions across the cell membranes, governs the membrane potential of the cell and initiates or regulates cell signaling. Transient receptor potential (TRP) channels, a group of nonselective cation channel proteins, play prominent roles in sensory physiology, such as detecting and responding to temperature, mechanical stress, pH, osmotic pressure, and pain, as well as contributing to olfaction and taste.1,2 In accordance with their diverse sensory responses, expression of TRP channels are widely distributed to different cell and tissue types where they perform the specialized roles. This makes TRP channels crucial for sensory signal transduction, cell homeostasis, neuronal excitability, tissue development, and disease development. All TRP channels are intrinsic membrane proteins with six transmembrane domains (S1–S6), intracellular N- and C-termini, and a channel pore region between S5 and S6.1–3 The intracellular termini vary significantly in length and the functional domains included among all TRP members and play crucial roles in the assembly of the channels and regulation of channel function.3
Himalayan poisonous plants for traditional healings and protection from viral attack: a comprehensive review
Published in Toxin Reviews, 2022
Shriya Pathania, Diksha Pathania, Priyanka Chauhan, Mamta Sharma
The neuroactive alkaloids can function as an agonist which excites a neuroreceptor or can function as an antagonist which blocks a certain neuroreceptor. Receptors on neuron cells are another major target for most alkaloids. These structurally resemble endogenous neurotransmitters such as glutamate, dopamine, acetylcholine, noradrenaline, and adrenaline (Mutschler et al. 2008). A few alkaloids repress the catalysts that separate synapses, like cholinesterase and monoamine oxidase. Neurotoxins also affect significant ion channel of neuronal cells, which includes Na+, K+ and Ca2+ channels, whichever by activating or inactivating them eternally. This activity stops neuronal signal transduction and blocks the activity of the nervous system and neuromuscular. The sodium, potassium ion ATPase is a significant ion pump in neuronal and other cells to keep an ion gradient important for action potentials and transport mechanisms (Wink 2000).
Treating status migrainosus in the emergency setting: what is the best strategy?
Published in Expert Opinion on Pharmacotherapy, 2018
László Vécsei, Délia Szok, Aliz Nyári, János Tajti
Rare manifestations of migraine, such as migraine with prolonged aura, persistent aura without infarction, and migraine aura status, together with ictal epileptic headache, represent diagnostic and therapeutic challenges in the clinical practice, especially in the ED setting. Migraine has several comorbid conditions, including epilepsy. The common pathophysiological mechanism of these clinical manifestations is not clear; however, the role of CSD and altered function of the Na+, K+ ion pump has been proposed. In the daily medical practice, ictal electroencephalography (EEG) recording is crucial for the differential diagnosis. If epileptic activity is present on EEG during ictal headache (i.e. we are dealing with an ictal epileptic headache), the therapeutic regime absolutely differs from the routine antimigraine treatment (i.e. it requires anticonvulsants instead of triptans or analgesics). Inadequate management of these patients can lead to a severe condition such as ‘status epilepticus migrainosus’ (i.e. a nonconvulsive status epilepticus manifesting merely in headache). SM or persisting aura without cerebral infarction can occur in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) patients as well [75–77]. Even more, drug-refractory migraine needs a worldwide consensus to have an adequate definition established, which should be added to the next version of the ICHD.
Introduction to biological complexity as a missing link in drug discovery
Published in Expert Opinion on Drug Discovery, 2018
Gary A. Gintant, Christopher H. George
It is already recognized that in silico models should not operate in out-of-gamut scenarios beyond the realms of physiological believability [61]. Conversely, there are arguments that data acquired in nonhuman animal models do not represent the full breadth of the “human gamut.” For example, in-breeding has produced widely-used animal models of limited genetic diversity although there is strain-to-strain variation in phenotype [62,63] and new resources exist to reconcile background genetic variation with biologic response [64] Moreover, in animals, the underlying biology may occupy a different physiological space (different networks/systems) in which the mechanisms of regulation and control are distinctly different from those in human. For example, mouse hearts beat much faster than human hearts (500–700 versus 50–70 bpm at rest), have different configuration of cellular ion pumps and exchangers for maintaining cellular ion fluxes during the cardiac cycle [65] and are resistant to ventricular fibrillation.