Neural Communication

Ramon y Cajal

Nobel Prize in Medicine 1906 Sketch of retina (1900)

1852-1934

The Nerve Impulse

Neural Communication

Otto Loewi

• Nobel Prize in 1936• Forced to leave

Germany in 1938• Became US citizen in

1941• Worked at Woods

Hole Institute• Name pronounced as

“low”

Loewi’s Experiment

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The first known neurotransmitter

• acetylcholine

• first neurotransmitter identified (by Otto Loewi, 1921)

• Movement: causes muscles to contract

• Memory: dies in Alzheimer’s disease

Autonomic NT’s

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Ach Pathways

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Synapse structures

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Steps

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Step 1

ACh Synthesis

Acetylcholine

Bonded to form

Step 2

Step 3

Step 4

Step 5

Step 6

Modifying Neural Messages

• drug agonists - enhance potency of neurotransmitter

• drug antagonists - reduce effectiveness

Agonist and AntagonistsNeurotransmitter molecule

Receiving cellmembrane

Receptor site onreceiving neuron

Agonist mimicsneurotransmitter

Antagonistblocksneurotransmitter

Pain Killers

• Endorphins • natural opiates• natural key• Morphine• Opium poppy• Agonist• Naloxone• Antagonist

Agonist and antagonist

Step 7

Reuptake and breakdown

AChE

Ach and AChE

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NT characteristics

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• the catecholamines:– Dopamine

• found at substantia nigra and limbic system

• regulates emotion & movement

– Norepinephrine• found in brain stem and subcortex

• regulates emotion, reward, sleep, mood

– Epinephrine• Found adrenal glands

• may help regulate blood pressure

Monoamine Neurotransmitters

Catecholamine synthesis

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Catecholamines

Catecholamine Pathways

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Neural Communication

Dopamine pathways

• Serotonin– found in raphe nuclei in

brain stem– regulates temperature,

sensory perception and sleep onset

– LSD and antidepressants affect serotonin (antidepressants particularly affect serotonin reuptake)

Monoamine Neurotransmitters

Serotonin

Serotonin Pathways

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Neural Communication

Serotonin pathways

Drug Effects

Classes of NT