What is the effect of curare poisoning on muscular contraction quizlet?
What is the effect of curare poisoning on muscular contraction quizlet?
These drugs are employed as relaxants of skeletal muscles during surgery to control convulsions. Research has shown that curare causes a weakening or paralysis of skeletal muscles by interfering with the transmission of nervous impulses between the nerve axon and the contraction mechanism of the muscle cell.
What causes the motor end plate to depolarize?
Depolarization of the motor end plate occurs when both receptors bind acetylcholine, causing a conformational change in the channel complex, opening it to the inward flow of positive ions (Figure 19-2). Cholinergic receptors are concentrated at the motor end-plate region of the sarcolemma in normal skeletal muscle.
How does curare paralyze a muscle quizlet?
Curare- is a poison that blocks neuromuscular transmission by binding to acetylcholine receptors. Acetylcholine cannot bind to the blocked receptors, resulting in paralysis.
Does curare poisoning affect the motor end plate or the axon terminal?
When a receptor is occupied by curare, ACh cannot bind to the receptor. Therefore although the motor nerves still conduct normal action potentials and release ACh, there is no resulting EPP in the motor end plate and no contraction, curare poisoning can cause death by asphyxiation.
How does curare interfere with the neuromuscular junction?
Curare acts as a neuromuscular blocking agent by binding to the acetylcholine receptor (AChR) at the neuromuscular junction and preventing nerve impulses from activating skeletal muscles (Bowman, 2006). However, it is not known if curare has a gender-specific effect on physical activity and whole body metabolic rate.
What is the effect of curare on muscle contraction when the nerve is stimulated?
CURARE (d-tubocurarine) reduces the responsiveness of skeletal muscle fibres to nerve stimulation1 by acting as a competitive antagonist to the transmitter acetylcholine (ACh)2.
What is the biochemical target of curare?
Curare acts as a neuromuscular blocking agent by binding to the acetylcholine receptor (AChR) at the neuromuscular junction and preventing nerve impulses from activating skeletal muscles (Bowman, 2006).
What triggers an end plate potential?
When a nerve impulse releases the neurotransmitter acetylcholine from the nerve terminal, it binds to channel-shaped receptor molecules on the end plate, opening the channels and allowing positively charged sodium ions to flow into the muscle cell.
What causes an end plate potential?
End plate potentials are produced almost entirely by the neurotransmitter acetylcholine in skeletal muscle. Acetylcholine is the second most important excitatory neurotransmitter in the body following glutamate. It controls the somatosensory system which includes the senses of touch, vision, and hearing.
What is the effect of curare?
How does curare inhibit acetylcholine quizlet?
Curare acts by binding temporarily to acetylcholine receptors on the postsynaptic cell and prevents acetylcholine from binding.
When was curare first used for medical use?
In 1850, George Harley demonstrated that curare could be used to treat tetanus and strychnine poisoning. By 1868, Claude Bernard and Alfred Vulpian had identified the site of action of curare as the motor end plate. From 1887, curare was marketed for medical use by Burroughs Welcome.
What happens to EPSPs after exposure to curare?
Effect of curare and hexamethonium on epsps (upper traces) produced by stimulation of the GDN (lower traces). A1, control. A2, epsps are abolished by 10 −4 M curare. A3, partial recovery after 15 min wash. Full recovery occurred after 30 min. B1, control. B2, epsps unaffected by exposure to 5 × 10 −4 M hexamethonium for 30 min.
What kind of depolarizing response does curare produce?
Curare (10−4 M) selectively antagonised the GDN-mediated epsps ( Fig. 19A) and the depolarizing response to DA, though it was not effective in all cases. ACh also produced a depolarization of the postsynaptic neurons which was blocked by curare but the DA and ACh receptors could be distinguished by hexamethonium ( Fig. 19B; cf. Ascher, 1972 ).
What is the function of the motor end plate?
Introduction: The motor end-plate is the connection between the motor nerveand the skeletal musclecell. Its function is to transmit the electrical signal (= action potential) from the nerve cell to the muscle cell. This is the stimulus that will make the skeletal cell contract.
