1. Drugs Affecting The Nervous System
UNIVERSITAS KLABAT Airmadidi, Manado SULUT - INDONESIA ☎ (62) ☏ (62) ✉
Drugs Affecting The Nervous System
Prepared by I Gede Purnawinadi, S.Kep.,M.Kes.

2. Overview of the Nervous System
The nervous system has two major divisions: the central nervous system (CNS) and the peripheral nervous system.
The CNS consists of the brain and spinal cord. The peripheral nervous system consists of all nervous tissue outside the CNS, including sensory and motor neurons.
The basic functions of the nervous system are as follows:
Recognizing changes in the internal and external environments.
Processing and integrating the environmental changes that are perceived.
Reacting to the environmental changes by producing an action or response.

4. Sympathetic and Parasympathetic Divisions
The autonomic nervous system has two divisions: the sympathetic and the parasympathetic nervous systems.
The sympathetic nervous system is activated under conditions of stress and produces a set of actions called the fight-or-flight response.
Conversely, the parasympathetic nervous system is activated under non-stressful conditions and produces symptoms called the rest-and-digest response.
The two primary neurotransmitters of the autonomic nervous system are norepinephrine (NE) and acetylcholine (Ach).

5. For information to be transmitted throughout the nervous system, neurons must communicate with one another and with muscles and glands.
In the autonomic nervous system this communication involves the connection of two neurons in series. As the action potential travels along the first nerve, it encounters the first synapse, or juncture.

6. Norepinephrine and Adrenergic Transmission
In the sympathetic nervous system, NE is the neurotransmitter released at almost all postganglionic nerves. The exception is sweat glands, in which Ach is the neurotransmitter.
NE belongs to a class of agents called natural catecholamines, all of which are involved in neurotransmission. Natural catecholamines also include epinephrine (adrenalin) and dopamine.
Adrenergic receptors are of two basic types, alpha receptors (α receptors) and beta receptors (β receptors).

7. Acetylcholine and Cholinergic Transmission
Nerves releasing Ach are called cholinergic nerves. There are two types of cholinergic receptors:
Nicotinic receptors. Receptors that were first discovered to bind to nicotine; located at the ganglionic synapse in both the sympathetic and parasympathetic divisions of the autonomic nervous system.
Muscarinic receptors. Receptors that were first discovered to bind to muscarine, a substance obtained from poisonous mushrooms; located on target tissues affected by postganglionic neurons in the parasympathetic nervous system