describe the role of gap junctions in electrical synapses
- coordinate biochem/electrical activity in cell- cell fashion
- involved in the synchronization of a cell network
what inherited human disorder is due to mutations in connexin 46,50?
cataracts
mutations in Cx26,30,31 lead to what kind of impairment?
hearing impairment
what is an electrical synapse?
neuron-neuron gap junction
what cell is responsible for most connexin expression?
- glial cells
what is the main connexin responsible for formation of electrical synapse?
- connexin36
Difference between electrical and chemical synapse in terms of depol/hyperpolarization responses?
E.Synapse– bi-directional signaling– no preference for depol/hyperpolarization
compare electrical/chemical synpases in terms of reaching subthreshold signals
E.synapse– passes subthreshold CURRENT
Chem. Synapse– generates subthreshold signal
describe the relevant properties of Electrical synapses in terms of:
- signaling direction
- duration of synaptic transmission/delay
- does it prefer hyper/depolarization response?
- bidirectional
- short synaptic delay
- no preference
explain how connexin expression is restricted to interneurons
- i.e. what interneuron subtypes are typically coupled together?
- connexin-mediated coupling between similar interneuron subtypes
- creates electrically coupled homocell. assemblies
what region of brain is cause of Cx36 KO motor impairment in mice?
- inferior olive E.synapse of cerebellum
result of Cx36 KO on olivary neuron synchrony?
- olivary neurons cannot synchronize
—> coordination of muscle contraction is impaired— ATAXIA
Role of Cx36 in retina?
- what happens in Cx36 KO?
responsible for elect. synapse that facilitates transmission from rod photoreceptors to ganglion cells
– Cx36 causes total night blindness
