Neural Communication The Nerve Impulse Neural Communication Otto

Neural Communication

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 KW 5 -2

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 KW 5 -17

Ach Pathways KW 5 -19

Synapse structures KW 5 -4

Steps KW 5 -5

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 Antagonists Neurotransmitter molecule Receptor site on receiving neuron Receiving cell membrane Agonist mimics neurotransmitter Antagonist blocks neurotransmitter

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

Agonist and antagonist

Step 7

Reuptake and breakdown

ACh. E

Ach and ACh. E KW 5 -11

NT characteristics KW 5 -9

Monoamine Neurotransmitters • 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

Catecholamine synthesis KW 5 -12

Catecholamine Pathways KW 5 -19

Neural Communication Dopamine pathways

Monoamine Neurotransmitters • 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)

Serotonin

Serotonin Pathways KW 5 -19

Neural Communication Serotonin pathways

Drug Effects

Classes of NT