* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Homework 3 - Stethographics, Inc.
Neural coding wikipedia , lookup
Neural modeling fields wikipedia , lookup
Electromyography wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Central pattern generator wikipedia , lookup
Caridoid escape reaction wikipedia , lookup
Microneurography wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Single-unit recording wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Neurotransmitter wikipedia , lookup
End-plate potential wikipedia , lookup
Nervous system network models wikipedia , lookup
Synaptogenesis wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Chemical synapse wikipedia , lookup
Biological neuron model wikipedia , lookup
Synaptic gating wikipedia , lookup
Homework 3: Synaptic Transmission Problem 1. A. B. Consider the stretch reflex as a model of monosynaptic reflex. Briefly describe the following: Sensory receptor involved The afferent neuron (also known as affector neuron) The efferent neuron (also known as effector neuron) The stimulus The response What types of electrical phenomena would you expect to be able to record along the reflex arc? In the axon of the sensory receptor In the axon of the motor neuron In the muscle Problem 2 Consider a motor neuron that receives excitatory input from afferent fibers of sensory neuron and inhibitory input coming from the motor cortex. Describe the electrical phenomena one can record from the cell body of the motor neuron. Discuss the role of motor neuron as an integrator of afferent and efferent information. Problem 3 A. Describe the events at the neuromuscular junction following arrival of AP. Specifically discuss: Presynaptic (in the axon terminal) changes in intracellular concentration of Na+, K+, Ca2+ Presynaptic events following increase of intracellular calcium concentration Events in the synaptic cleft Postsynaptic (in the muscle) changes in intracellular concentration of Na+, K+, Ca2+ B. Describe what will happen to the sequence of events discussed in A. following application of: Na+ channel blocker Ca2+ channel blocker Botulinum toxin 1 Homework 3: Synaptic Transmission Case Study – Group seeks Botox warning after 16 death reports By Lisa Richwine Thu Jan 24 2008, 8:16 PM ET WASHINGTON (Reuters) - Botox and a similar injection should come with stronger warnings following reports of 16 deaths after the botulinum toxin spread inside the body, a U.S. consumer group said on Thursday. Public Citizen asked U.S. authorities to require the strongest possible warning, highlighted in a "black box," on Allergan Inc's Botox and Solstice Neurosciences Inc's Myobloc. Botox is famous for smoothing facial wrinkles but also has approved medical uses such as treating cervical dystonia, or rigid neck muscles. Myobloc is cleared only for the neck condition. Both injections are made with forms of the botulinum toxin, which blocks nerve impulses to muscles and makes them relax. Public Citizen said it reviewed 180 reports submitted to the Food and Drug Administration by manufacturers involving patients injected with Botox or Myobloc. The reports detailed cases of muscle weakness, difficulty swallowing or aspiration pneumonia, a serious condition caused by breathing a foreign material into the lungs. Reports to the FDA do not prove a product caused a particular problem, but the agency uses them to look for patterns of potential complications. Experts believe most problems are under-reported to the agency. "There are no safety issues raised in the petition that are not already addressed in the labeling for Botox," Allergan said in a statement. The company said it is in frequent dialogue with the FDA to ensure proper labeling and also submits all information it receives on adverse events whether or not they are related to the drug. Solstice Neurosciences said in a statement that it recently submitted safety data to the FDA and it stood behind the current prescribing information. Allergan projected in November that worldwide sales for Botox would top $1.1 billion in 2007. Sixteen cases reported to the FDA were fatal, including four involving children under 18, Public Citizen said. Eighty-seven patients were hospitalized. Dr. Sidney Wolfe, director of Public Citizen's Health Research Group, said such problems can occur if botulinum toxin spreads from the injection site to places such as the esophagus, causing partial paralysis. Instructions for Botox and Myobloc mention the issue but it is easy to miss, he said. Public Citizen asked the FDA to order a black-box warning to highlight the concern, plus a letter to doctors. The agency also should require a consumer-friendly guide explaining the risks that would be handed out by doctors when the drug is injected, the group said. "These significantly improved warnings to doctors and patients would increase the likelihood of earlier medical intervention when symptoms of adverse reactions to botulinum toxin first appear, and could prevent more serious complications, including death," Public Citizen said in a petition to the FDA. Early symptoms include dry mouth, difficulty breathing or swallowing, slurred speech, drooping eyelids and muscle weakness. The group said European regulators have warned physicians to watch for signs of botulinum toxin complications. FDA spokeswoman Karen Riley said the agency would not comment while the Public Citizen petition was under review. Questions: What botulinum toxin does to neurons? Why Botox is popular in the first place (need cellular lever explanation)? What is the mechanism of “muscle weakness” in some patients injected with Botox? 2