3 - Neurotransmitters, ACh

Neurotransmitters

The nervous system contains a variety of _________, each of which interacts with a specialized receptor

Ach (Acetylcholine)

neurotransmitter that have received the most study

Ach (Acetylcholine)

first ever neurotransmitter that was discovered

Monoamines

have also received most study on

• Dopamine

• Norepinephrine

• Serotonin

Monoamines: (3)

series of enzymes

The synthesis of these neurotransmitters is controlled by a _________

• Glutamate

• GABA

• Glycine

Several amino acids also serves as neurotransmitters, the most important of which are:

Glutamate

serves as an excitatory neurotransmitter

• GABA

• Glycine

serves as inhibitory neurotransmitters

Peptide neurotransmitter

consists of chains of amino acids

Peptide neurotransmitters

like proteins, they are synthesized at the ribosomes according to sequences coded by the chromosomes

Peptide neurotransmitters

often don’t cause direct excitation or inhibition

Peptide neurotransmitters

they modulate the effects of classical neurotransmitters

• neuromodulator

• neurotransmitter

That means most peptides are better described as ________, even though they're released like __________.

Endogenous opiods

the best-known class of peptides in the nervous system

• opium

• heroin

Endogenous opiods whose effect are mimicked by drugs such as:

• Adenosine

• Nitric oxide & Carbon monoxide

Neuromodulators:

Adenosine

a nucleoside that has inhibitory effects on synaptic transmision

• is released by neurons and glial cells in the brain

Nitric oxide, Carbon monoxide

soluble gases, that can diffuse out of the cell in which they are produced and trigger the production of messenger adjacent cells

• Acetylcholine (ACh)

• Dopamine (DA)

• Norepineohrine (NE)

• Serotonin (5-HT)

• Gamma-aminobutyric Acid (GABA)

• Glycine

• Opiods

• Adenosine

• Nitric oxide (NO)

Neurotransmitters:(9)

ACh

the primary neurotransmitter secreted by efferent axons of the CNS

ACh

all muscular movement is accomplished by the release of this neurotransmitter

ACh

also found in the ganglia of the ANS and at the target organs of the parasympathetic branch of the ANS

ACh

Because ___ is found outside the CNS in location that are easy to study, this neurotransmitter was the first to be discovered, and it has received much attention from neuroscientists

Acetylcholinergic

Some terminology: “These synapses are said to be _______”

Ergon

Greek word for work

• dopamine

• serotonin

Thus, dopaminergic synapses releases _______, serotonergic synapses release ______, and so on

facilitatory

The effects of ACh released in the brain are generally _________

• means that acetylcholine (ACh), when released in the brain, typically enhances or promotes neural activity, rather than suppressing it

• dorsolateral pons

• basal forebraib

• medial septum

Acetylcholinergic neurons locations:

Dorsolateral pons

responsible for eliciting most of the characteristics of REM sleep

Basal forebrain

involved in activating the cerebral cortex & facilitating learning, especially perceptual learning

Medial septum

control the electrical rhythms of the hippocampus and modulated its functions, which include the formation of particular kinds of memories

• Ionotropic ACh receptor

• Metabotropic ACh receptor

2 types of ACh receptor:

ACh receptors

These receptors were identified when investigators discovered that different drugs activate them

Ionotropic ACh receptor

stimulated by nicotine

Nicotine

drug found in tobacco leaves

Nicotiniana tabacum

latin name of Nicotine

Metabotropic ACh receptor

stimulated by Muscarine

Metabotropic ACh receptor

control ion channels through the production of second messenger, their actions are slower and more prolonged than those of nicotinic receptors

Muscarine (Armanila Muscaria)

drug found in the poison mushroom

• Nicotine receptors

• Muscarine receptors

Consequently, these two ACh receptors are referred to as:

Muscarinic receptors

The CNS contains both kinds of ACh receptors, but ________ predominate

Axoaxonic synapses

Some nicotinic receptors are found at _________ in the brain, where they produce presynaptic facilitation