Hyperkalemic Period Paralysis (HyperPP) is disease which causes sudden periods of extreme muscle weakness or paralysis (GHR). It is inherited as an autosomal dominant trait (Brown 1991). HyperPP usually begins during infancy or early childhood and as the individual affected grows older the frequency of the attacks lessen (GHR). Some of the triggers include, resting after exercising, consuming potassium rich foods, such as bananas, fatigue, and ingesting alcohol. After an attack of paralysis has occurred, muscle strength usually returns to normal, however, there might be some stiffness (GHR).
Molecular basis of disease
Normal functioning sodium channels play a fundamental role in physiology. Sodium channels transmit depolarizing impulses promptly
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One of the issues lie in the voltage sensitive sodium channel. It has been shown that many people with Hyperkalemic periodic paralysis has low serum potassium levels during attacks of paralysis. While the normal level for potassium in the blood is between 3.5-5 millimoles per liter (Mayoclinic) during a paralytic episode, the potassium level rises to 6-7 millimoles per liter. Like with hypokalemia, hyperkalemia paralysis usually occurs during a period of rest after exercise. During a hyperkalemic attack, depolarization occurs by induction of extracellular potassium. In a hyperkalemic period of paralysis, a potassium related abnormality of sodium conductance in the pathogenesis has been observed (Brown 1991). Hyperkalemic has been proven to be tightly linked to the tetrodotoxin sodium channel (TTX) (Brown 1991). Hyperkalemic periodic paralysis occurs due to a mutation in the skeletal muscle sodium channel complex (SCN4A) (Ebers et al. 1991). There is a defect in the normal voltage dependent inactivation of the sodium channels (Cannon et al. 1991). Whenever there is an elevation of potassium, even a slight one, the gating mode in the channels, persistently reopen and sometimes stay open for long moments (Cannon et al. 1991). Hyperkalemia periodic paralysis manifests because of the inactivation of the un-mutated sodium channels via the membrane voltage
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
Nerve stimulation was induced for every fifteen seconds at an increment frequency of 0.5 pps (parts per seconds), 1.0 pps, 2.0 pps, 4.0 pps, 8.0 pps, 15 pps, and 25 pps. Every increment trial had a thirty-seconds waiting period. To witness the effects of tubocurare on muscle activity, the baseline was maintained between 20-30 grams and a control was established by turning the stimulator on repeat for 60-120 seconds. Then 0.25 ml of tubocurare was infused into the gastrocnemius muscle. The data was recorded for ten minutes.
Hypertrophic Cardiomyopathy, also known as HCM, is a type of heart disease that affects the Cardiac Muscles and Cardiac Muscle cells. This disease occurs if the Cardiac Muscle cells enlarge, which causes the wall of the heart’s ventricles (most often the left ventricle) to thicken. It can also cause stiffness in the ventricles, as well as mitral valve and cellular changes.
MG patients have only one-third of the normal numbers of acetylcholine receptors which causes weak and easily fatigued muscles. The muscles under voluntary control are affected. The heart muscles, which are under involuntary control, are not affected. In MG generally, the muscles that control the eye and eyelid movement are affected first, causing the eyelids to sag. Some MG patients may develop double or blurred vision. When only the eye muscles are affected, the disease is known as Ocular Myasthenia. Disease symptoms affecting the facial muscles leads to limitations of facial expressions. Victims have difficulty smiling and expressing emotions on their face.
Spinal Muscular Atrophy, also known as “SMA” is a genetic and also a motor neuron disease that affects the area of the nervous system that controls your voluntary muscle movements such as walking, crawling, and swallowing. When someone acquires this condition their muscles start to shrink as a cause to the muscles not receiving signals from the nerve cells in the spine that control function. Spinal Muscular Atrophy is a rare but serious condition.
Myasthenia Gravis is an autoimmune neuromuscular disorder. The term "myasthenia" is Latin for muscle weakness, and "gravis" for grave or serious. It is characterized by random weakness of voluntary muscle groups. Muscle groups most commonly affected include the eye muscles, facial, chewing and swallowing muscles, and shoulder and hip muscles. It is typical for a myasthenic patient to have a flattened smile, droopy eyes and an ineffective cough due to weak expiratory muscles, are all also associated with MG. Most myasthenic patients usually don't complain of extensive feelings of fatigue. They experience localized fatigue in specific, repeatedly used muscles. Today, MG is one of the most thoroughly understood neurological disorders, which has lead to treatments, which enormously improves the length and quality of life of myasthenics.
problems within the specific ion channels known to cause the disease. The goal of the
Hyponatremia treatment that occurs too rapidly is associated with the formation of demyelinating lesions in the pons known as CPM. These lesions lead to permanent neurological damage (Gheorghita et. al 2010). Physicians and patients should not fail to treat severe hyponatremia in an effort to avoid CPM development. Failure to treat hyponatremia may lead to severe brain damage, coma, or even death (Schuster et. al 2009 and Gheorghita et. al 2010). Symptoms of CPM have been seen to improve with time which plays the most critical role. Even treating hyponatremia with a hypertonic saline solution still raises the most important risk of developing CPM but a good neurological outcome has been seen in several cases when enough time and one of the above therapies are done.
The occurrence of action potential is a very short process. When action potential occurs in the neuron the sodium channels open along the axon and sodium comes in. Because the sodium is positive it make the inside of the axon positive. When both the inside and outside are comparative in charge the sodium storms rushing in and starts the depolarization of the action potential. After this happens the sodium channels begin to close and the potassium channels begin to ...
6. McFadzean I and Gibson A (2002) “The developing relationship between receptor-operated and store-operated calcium channels in smooth muscle”. British Journal of Pharmacology 135: 1-13. Online, available at http://onlinelibrary.wiley.com/doi/10.1038/sj.bjp.0704468/pdf -Accessed 23/11/2013.
The refractory period, which is before the resting potential is rebalanced by the pump, prevents the action potentials from traveling both ways down an axon at one time due to the neurons inability to respond to stimuli as a result of the imbalance of Na+ and K+ ions. This entire process repeats in a sort of chain reaction down the axon of the neuron until the impulse reaches the synapse, which is the gap between two neurons. When the neuron is depolarized, voltage-gated Ca2+ channels are activated and opened, releasing Ca2+ into the cytoplasm of the presynaptic neuron. This flow of Ca2+ ions causes synaptic vesicles to fuse with the cell membrane and release the chemical messengers (neurotransmitters) which diffuse across the synapse to the postsynaptic neuron from an area of high concentration to low concentration. The protein receptors, located on the dendrites of the postsynaptic neuron then receive the neurotransmitters which act like the stimulus that then converts the signal back to an electrical signal so the action potential can continue to
Action potential is what allows for nerve impulses. The process of action potential begins when there is a difference in concentration of ions outside and inside of the neuron. Before this process begins, the neurons are in a state called resting potential. In this state, neurons are negativelty charged at -70 mv. If an electrical stimulus is applied, sodium dependent gates open and positive sodium ions to rush in. Now the neuron is positively charged. The added sodium creates what is known as a 'spi...
Did you ever awaken and find yourself unable to move? Perhaps you sensed a presence in your room or a pressure on your chest. This is sleep paralysis. It is a common disorder that affects millions of people. Most believe it occurs as we are on the edge of REM sleep. The disorder has been connected with such hallucinogenic events such as alien abduction or an evil presence. Sleep paralysis is an inability to move or speak, occasionally accompanied by hallucinations, for up to several minutes upon awakening or just before falling asleep.
You are lying in bed taking a much-needed nap. You have had a long day and this little refresher is just what you need. You are slowly becoming awake and aware of what is going around you. You can hear someone in the kitchen cooking and through the open window by your bed you can hear the sounds of the kids of the neighborhood jumping rope and playing hand games. You can even hear Old Mrs. Jones yelling at Little Johnny for running all over her flowers. You have been sleeping for about an hour and you feel that it is about time to get up. So you open your eyes, or at least you think you do. For reason some they are not open. So you think to yourself, "That is odd, I thought I mentally told my eyes to open?" So you try again, and this time you hear your voice in your head say, "Eyes open;" but again nothing happens. Now you think maybe you are really out of it, and that you must be extremely tired and just need to rub your eyes a little to get them moving. So next you try to move your arm, only it is stuck. Then you realize that your entire body is stuck. You think that this situation has to be unreal. You are awake; you have to be. You can obviously think to yourself, and you can hear everything that is going on inside and outside, but why are you not moving? You try to open your mouth and call for help, but you cannot do that either. You are completely paralyzed! Then you start to think this that is some sort of nightmare-and it is, except it is very much real. You are experiencing sleep paralysis.