Solution-Differences between parasympathetic and | Homework Helpers
1) Briefly present the structural and functional relationship of peripheral nervous system
2) Describe the differences between parasympathetic and sympathetic divisions of autonomic nervous system
3) Describe and compare neurotransmission and neurotransmitters in both divisions of autonomic nervous system
4) Analyze the process of synthesis, storage and inactivation of neurotransmitters
5) Differentiate the main categories of neurotransmitter receptors
6) Compare the drugs acting on cholinergic receptors to drugs acting on adrenergic receptors
7) Functional responses mediated by the autonomic nervous system
8) Drugs acting on autonomic nerves and receptors
9) Compare mechanism of action of drugs that are called agonists to antagonists to nicotinic or muscarinic receptors.
10) Compare the mechanism of action of drugs that are called agonists to antagonists to alpha or beta adrenergic receptors.
11) Explain the purpose of use of drugs that inhibit neurotransmitter synthesis
12)Explain the rationale of clinical usage of cholinesterase inhibitors
13) Explain the rationale of clinical usage of drugs that promote neurotransmitter release or interfere with storage
14) Compare the mechanism of action of sympatomimetics and sympatholytics
15) Identify the differences between direct-acting sympatomimetics and indirect-acting sympatomimetics.
16) Briefly present direct and reflex cardiovascular actions of adrenergic agents.
17) Give examples of most commonly used beta receptor antagonists.
18) Describe the difference between non-selective and selective beta receptor antagonists.
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Answer1
Peripheral nervous system (PNS) is associated with the skeletal muscles, in which the action is propensities through the neuromuscular junction or the musclesfibres itself and hence cause action with respect to muscle tone. The cascade of PNS is divided into both somatic and autonomic nervous system. The neurotransmitter that acts on the PNS are acetylcholine and noradrenaline. Other than this, there are certain non-adrenergic and non-cholinergic transmitters (NANC), which also binds as neurotransmitter of peripheral nervous system. Popular example of these NANC are GABA, dopamine, nitric oxide, neuropeptide Y and substance P. Apart from the endogenous neurotransmitters, it is important to discuss the mechanism of action, structure and function relationship of the agents and receptor in conjunction to the agents which act over it. The agents, which act for PNS are broadly, can be classified as neuromuscular blocking agents and directly acting agents.
In brief, neuromuscular agents are (i) non-depolarising in nature that acts as competitive blockers; and (ii) depolarizing in nature. These agents act over the end plate of the skeletal muscle fibers. In particular, the competitive blockers have affinity for the cholinergic NM receptors (nicotinic-muscarinic) present at the end plate of muscle fibers. Nm receptors is composed of five subunits (two a, ß, e/? and d), which are arranges in rosetta arrangement around the Na+ channel. The two a subunits contains two cholinergic binding sites (Ach) that are negatively charges and binds with the cationic head group of acetylcholine. The corresponding binding leads to opening of the Na+ ion channel gates. It is hence the agents that act over these receptors have two or more quaternary N+ atoms and make the possible binding with the receptor.
