[Last updated:]

Feb 23, 2021 


PSY 340 Brain and Behavior

Class 08: Chemical Events at the Synapse [Outline]


Some thought questions:
To answer these questions, we must understand the chemical events at the synapse & what happens with the neurotransmitters secreted there.

Chemical Activity at the Synapse: Summary

            Activity at the Synapse

Illustrating the Synapse


[Synaptic Bouton]

A. Types of Neurotransmitters

Some Important (but not all) Functions & Facts
Amino Acids  Glutamate (Glu) excitatory
  GABA (Gamma-aminobutyric acid) inhibitory
Modified Amino Acid Acetylcholine (ACh)
 Monoamines Indoleamine   derived from tryptophan (an amino acid from diet)

 Serotonin (5-HT or 5-hydroxytryptamine) modulation of emotion
  Catecholamines derived from phenylalanine (an amino acid from diet) -> Tyrosine -> Dopa -> DA/NE/Epinephrine (see below) 

 Dopamine (DA) Muscle coordination
Creates salience/urgency/captures attention

 Norepinephrine (NE) modulation of emotion
   Epinephrine (Adrenaline) stimulates sympathetic nervous system
Other Peptides
(ca. 40 different types) 

Endorphins (& enkephalins) suppresses transmission of pain by hyperpolarizing neurons which send out Substance P
Substance P dull chronic pain (e.g., cancer, nerve tissue damage)
Neuropeptide Y stimulates feeding and fat storage
Purines  Adenosine, ATP,
et al.
Adenosine => signals onset of sleep
ATP => basic energy in cell
Gases  NO (Nitric Oxide)  dilates blood vessels; created as needed

Sources: Kalat (2005, 2007, 2009. 2016), Kimball (2005)

B. Transport & Storage of Neurotransmitter/Release and Diffusion of Neurotransmitters

C. Receptor Activation on the Postsynaptic Cell

post synaptic

1. Ionotropic

2. Metabotropic & Second Messenger Systems

Neuropeptides (endorphins, substance P, neuropeptide Y, etc.) = neuromodulators

Variations in Receptors

Drugs Binding to Receptors

D. Inactivation and Reuptake of Neurotransmitters

E. Negative Feedback from Postsynaptic Cell

F. Electrical Synapse (Gap Junction)


G. Hormones

Endocrine Glands   
  Hypopituitary System
    Pituitary Gland and the Hypothalamus

This page was first posted January 18, 2005.