Compare and contrast the two different major classes of ion channels. Explain the difference between full agonists, partial agonists, antagonists, inverse agonists.
Topic: Nursing research article (Ion Channels)
Compare and contrast the two different major classes of ion channels.
Explain the difference between full agonists, partial agonists, antagonists, inverse agonists.
Responses need to address all components of the question, demonstrate critical thinking and analysis and include peer-reviewed journal evidence to support the student’s position.
Please be sure to validate your opinions and ideas with in-text citations and corresponding references in APA format.
Please review the rubric to ensure that your response meets the criteria.
Estimated time to complete: 3 hours cholarly resource, ideally within the last 5 years. Journals and websites must be cited appropriately. Citations and references must adhere to APA format.
Ion channels are remarkable proteins, present in the lipid bilayer membrane of both animal and plant cells and their organelles, such as nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, chloroplasts, and lysosomes.
When we google the word “ion channel,” about 80,000,000 results pop up within 0.45 s. Scientists have been working on these amazing transmembrane proteins since the beginning of the last century, which has resulted in three sets of Nobel prizes in 1963, 1991, and 2003.
Sir John Carew Eccles, Alan Lloyd Hodgkin, and Andrew Fielding Huxley in 1963 received Nobel Prize for Physiology and Medicine for their discoveries concerning the ionic mechanisms involved in excitation and inhibition in the peripheral and central portions of the nerve cell membrane.
Similarly, Erwin Neher and Bert Sakmann in 1991 proved that cell membranes have individual ion channels through which tiny currents can pass, which are big enough to generate communications between pre- and postsynaptic neurons by converting chemical or mechanical events into electrical signals.
The Nobel Prize in Chemistry for 2003 was shared between two scientists Agre and Roderick MacKinnon who have made fundamental discoveries concerning how water and ions move through cell membranes.
In this book, we have nine very diverse and informative chapters including this introductory chapter on the importance of both cations and anions passing through these ion channels.
First chapter is the introductory chapter which briefly overview the other eight chapters included in this book, as well as discusses the diversity and classification of ion channels, nature and number of gating for these ion channels along with shedding some light on Channellopathies.
Second chapter deals with the voltage-gated sodium channels in drug discovery.
Sodium channels are the very first one to be discovered when Hodgkin and Katz were performing their experiments on squid axons showing that there would be no action potential if sodium ions are not present in the extracellular fluid.
In this chapter, genetic evolution and subtype distribution of this super family of voltage-gated sodium (Nav) channels are introduced, and there is a discussion about how the changes in the structure alter their functions.
Third chapter argues the modulation of Nav by small and large molecules, along with the discussion on the major challenges for the Nav-targeted drug discoveries.
Fourth chapter is taking us to a striking journey about how the genetic mutations bring change in their product proteins and resultant disorders such as Dravet syndrome. SCN1A gene is responsible for this condition and there is a word of caution for the medical practitioners to not prescribe sodium channel blockers for the epileptic patients with this mutation, as the medicine will aggravate their condition.
Fifth chapter is about potassium channels: there are many different types of the potassium channels (many more than sodium ion channels). In this chapter, authors have discussed the role of two gap junction proteins—connexins and pannexins—in maintaining the homeostasis of potassium ions, taking cochlea as an example. Mutation in gap junction gene results in 50% of prelingual, recessive deafness. Authors developed a novel method for the early detection of the genetic mutations for the inner ear impairment.
Sixth chapter is dealing with the structure and function of L-type calcium channels and how voltage-gated calcium channels (VGCCs) manage the electrical signaling of cells by allowing the selective-diffusion of calcium ions in response to the changes in the cellular membrane potential. Among the different VGCCs, the long-lasting or the L-type calcium channels (LTCCs) are prevalently expressed in a variety of cells, such as skeletal muscles, ventricular myocytes, smooth muscles, and dendritic cells and form the largest family of the VGCCs. Their wide expression pattern and significant role in diverse cellular events have made these channels the major targets for drug development.
Seventh chapter is about the regulation of pain through calcium channels. In this chapter, authors present a large body of clinical, biochemical, biophysical, pharmacological, and genetic evidences pointing toward calcium-permeable channels as the key players in pain conditions.
The primary goal of this chapter is to present an overview of the different classes of calcium-permeable channels and how they change to modulate the sensation of pain in acute and chronic states.
Eighth chapter deals with the transient receptor potential (TRP) ion channels, from their distribution to their assembly. TRP ion channel superfamily is widely distributed from neuronal to nonneuronal tissues by serving as cellular sensors. TRP subunits can form both homomeric and heteromeric channels which are present either in the same subfamily or in the different subfamilies and diversify TRP channel functions.
Ninth chapter discusses about the types of anionic and chloride channels present in the mitochondria. There are many types of chloride channels present in mitochondria, but two types are of major interest, i.e., one which is present in the inner mitochondrial membrane, responsible for the oscillations of membrane potential and the chloride intracellular ion channel (CLIC) localized in the cardiac mitochondrial membranes.
These anion channels are very important both in health and diseased conditions. These channels are important for the regulation of PH and ROS along with the synchronization of the mitochondrial membrane potential.
In the following pages of Chapter 1, we will be looking at the role of gating in ion channels for the maintenance of normal physiology and how any of these alterations in the gating result in the channelopathies.
Before going any further, we would like to acknowledge the sculpture called the birth of an idea. It is a 1.5-m tall figurine of KcsA potassium channel, made up of wires and blown glass, representing the channel’s lumen. This statue was commissioned to Julian Voss-Andreae by Nobel Prize winner Roderick Mackinnon.