neurotransmission Flashcards
cell types in the brain
- neurons
- astrocytes
- microglia
- endothelial cells & pericytes
parts of a neuron
nucleus
cell body
dendrites
axon
4 types of astrocytes in the human cortex
- protoplasmic
- interlaminar astrocytes
- fibrous astrocytes
- polarized astrocytes
function of astrocytes
- brain support
- release & take up NT (e.g. glutamate)
- express receptors (e.g. NMDA)
- regulate synaptic transmission
- conduct electrical events via gap junctions
- brain pathology e.g. form scars
- immune activation
protoplasmic astrocytes
- most common type
- reside in layers 2-6 of the cortex
- domain structure ~ 1 astrocyte might cover 10 nerve cell bodies
fibrous astrocytes
- found in the white and grey matter
- their processes intermingle (dont form a domain structure)
- serve a support role and respond to brain injury
gliotransmission & glioneuronal functional units
- describes the process of release of NT from astrocytes and acting on neurons
- greatly enlarged the role of astrocytes in normal brain function
microglia
- surveyors of the brains micro-environment
- resident macrophages of the brain
- mediate the brain immune response
- phagocytose debris
- help sculpt the brain during development
what is the relationship between brain endothelial cells and pericytes
-pericytes encase endothelial cells in brain capillaries and maintain the BBB
how is the termination of a transmitters action achieved?
achieved by either metabolism and/or re-uptake into neurons and/or glial cells (astrocytes) by specific transporter proteins e.g. anti-depressants
chemical neuroanatomy
the study of the anatomical localization of NT systems
a drug will not only depend on which NT system it modulates/mimics but also on the anatomical localization of the NT system
amino acid derivatives
GABA, glutamate, glycine
neuromodulators
produce slower pre and post-synaptic responses. released by nerve cells & astrocytes (e.g. adenosine)
neurotrophic factors
released by non-neuronal cells (e.g. astrocytes, microglia) and neurons and work over long-time scales
act on tyrosine-kinase receptors to mediate growth, morphology, functional properties, survival promoting effects in the nervous system
fast acting neurotransmitters
work via ion channels (e.g. glycine, GABA, glutamate
slow acting neurotransmitters
work via G-protein coupled receptors (DA, neuropeptides, GABA, ACh)
