The Synaptic TransmissionCharacteristics- Single direction (presynaptic → postsynaptic)- Synaptic delay (0.3-0.5ms)-Easilytired (limited neurotransmitterstorage)- Easily affected (internalenvironment, drugs)Type-Excitatorypostsynaptic potential (EPSP)(Excitationtransmission)- Inhibitory postsynaptic potential (iPsP) (Inhibition transmission)
The Synaptic Transmission • Characteristics - Single direction (presynaptic → postsynaptic) - Synaptic delay (0.3-0.5ms) - Easily tired (limited neurotransmitter storage) - Easily affected (internal environment, drugs) • Type - Excitatory postsynaptic potential (EPSP) (Excitation transmission) - Inhibitory postsynaptic potential (IPSP) (Inhibition transmission)
Excitatory Postsynaptic Potential (EPSP)CI-+ImpulseANatAxonK+XAxonterminal(a)PostsynapticdendriteDepolarizationNeurotransmitter-RecordVmmoleculesNa+NatNatSynaptiocleftEPSPVoCytosol65mV02468Transmitter-gated(b)(c)Timeframpresynapticactionpotential (msec)ion channels
Excitatory Postsynaptic Potential (EPSP) K + Na+ Cl- + - + + + + + + + - - - - - - - Depolarization
InhibitoryPostsvnaptic Potential (iPSP)ImpulseCIAxonNatAxonterminal(a)PostsynapticdendriteHyperpolarizationRecordVmNeurotransmittermoleculesSynaptic-cleltIPSPCytosol65mV-C604Transmiter-gated(b)(c)Timefrompresvnapticactionpotential(msec)ionchannels
Inhibitory Postsynaptic Potential (IPSP) K + Na+ Cl- + - + + + + + + + - - - - - - - Hyperpolarization
The Chemical SynapsespresynapticpostsynapticElectrical action potentialchemicalResponsesignalChemicalsynapses
The Chemical Synapses