Biology 3240 Intro Cellular Neurobiol, Fall '09
Key Words & Concepts: Lectures 22-32
This page will offer some key words and ideas from lectures, provided as rough study guides.
Larry Okun, Doju Yoshikami
(to Suggested Readings instead)
Lecture 22 10/23/09
A synapse that has both electrical and chemical transmission (Fig. 9.3).
Excitatory postsynaptic potential (EPSP) at the neuromuscular junction (NMJ) (Fig. 9.5).
Synonym for EPSP at NMJ is the endplate potential (EPP).
Distribution of nAChRs at the postsynaptic membrane 'mapped' by iontophoresis (Figs. 9.7 & 9.9).
Ionic basis of the EPSP (Figs. 9.11 and 9.12 and Box 9.1).
[Exercise: How will Vrev change if [K+]out were increased?
If [Na+]out were decreased? If the synaptic gNa were increased?]
EPSP and EPSC under current- and voltage-clamp conditions, respectively.
Lecture 23 10/28/09
Microscopic and macroscopic synaptic currents (Fig. 9.13).
Non-linearities of the postsynaptic response.
The dose-response curve for ACh at the endplate is sigmoid.
At low ACh concentrations, response is proportional to [ACh]2.
Electrical vs. chemical saturation at high ACh concentrations.
Another functional property of ionotropic receptors.
Receptor desensitization (Fig. 9.17).
Ionic mechanism underlying inhibitory synapses (Fig's. 9.14 & 9.15).
[Exercise: regarding Fig. 9.14, how would Vrev change if [Cl-]in were increased?]
Presynaptic inhibition (Fig. 9.16).
Lecture 24 10/30/09
Comparison of the postsynaptic response in skeletal versus cardiac muscle to a brief pulse of ACh.
Comparison of the respective pharmacologies of the receptors involved.
[Exercise: How would you show that an increase in gK is involved in the
ACh-induced hyperpolarization of cardiac muscle?]
Direct versus indirect transmitter action (Fig 10.1, Handout 1.1).
GPCRs or metabotropic receptors (Fig 10.2).
Second messengers.
GPCR families.
Effectors (Handout 1.2).
G-protein: αβγ trimer, GTP binding, GTPase (Fig. 10.3).
Cardiac AP (Fig. 10.8A).
Examples of modulation of ion channels by G proteins
Direct modulation
ACh-induced increase in cardiac IK mediated by Kir channel (Fig. 10.4 & 10.5)
Direct modulation by G proteins (another example)
NE-induced decrease in neuronal ICa (Fig. 10.6 & 10.7)
Indirect modulation by G proteins
NE-induced increase in cardiac ICa involving adenylyl cyclase (Fig. 10.8, 10.9, & 10.10)
Lecture 25 11/2/09
Indirect modulation by G proteins (cont'd)
Phosphorylation of (biochemically purified) CaV reconstituted in a planar lipid bilayer
increases the activity of the channel (Fig.10.11).
NE can act on CaV of a (sensory) neuron through the 2nd messengers DAG and IP3
(Fig. 10.13, see also Handout 1.2).
ACh initiates intercellular signaling (between endothelial and smooth muscle cells) mediated by NO
(Fig. 10.15, see also Handout 1.2).
Indirect modulation by Ca++
Entry of Ca++ through nAChR can produce inhibition by activating KCa (Ca++-activated K channel)
(Fig. 10.16).
Ca++ is an important 2nd messenger (Fig. 10.17).
Transmitter release and presynaptic Vm (Fig. 11.1).
Synaptic delay (Fig. 11.2).
Lecture 26 11/4/09
Entry of Ca++ is necessary for transmitter release (Fig. 11.3).
Increase in intracellular [Ca++] induces transmitter release (Fig. 11.6).
Spontaneous miniature endplate potentials (mepp's) (Fig. 11.7).
Evidence for involvement of ACh released from presynaptic nerve terminal.
Relationship between (evoked) epp and mepp (Fig 11.8 & 11.9)
Quantal (or quantum) content (m) determined by 'failures' and by {mean epp}/{mean mepp}
[Exercise: use data in Fig. 11.9 to calculate m by these two approaches.]
Lecture 27 11/6/09
Molecular biology of synaptic vesicle exocytosis
Lecture slides available as a PDF file here.
Lecture 28 11/9/09
Synaptic vesicle recycling
Lecture slides available as a PDF file here.
Lecture 29 11/11/09
Involvement of Ca++ in transmitter release (cont'd)
Use of light-sensitive chelator to trigger increase in [Ca++]in and transmitter release (Fig. 11.6).
Spatial domain of Ca channels (Fig. 11.4).
Close proximity of Ca channel and transmitter release site (Fig. 11.5).
Relationship between transmitter release (quantal content -- 'm'), [Ca++]out, and ICa.
Ca++ ions act cooperatively to effect transmitter release.
Estimates of the number of ACh molecules in a quantum.
By mimicking a mepp with iontophoretically applied ACh (Fig's. 11.10 & 11.11).
From the voltage change produced by the opening of a single ACh-gated channel.
The density of receptors at the postsynaptic membrane (Fig. 11.12).
Metabolism of neurotransmitters (Ch 13).
Chemical structures of neurotransmitters (Fig. 13.2).
Structure of a catecholamine (CA).
Detection of CA by electrochemistry (redox potential) (Fig. 11.25).
Lecture 30 11/13/09
Metabolism of neurotransmitters (cont'd)
ACh release from sympathetic ganglia measured biochemically (Fig. 13.4).
Biochemistry of:
Acetylcholine (Fig. 13.5)
Norepinephrine and dopamine (Fig. 13.6 & 13.7)
Serotonin (5HT) (Fig. 13.8)
GABA (Fig. 13.9)
Glutamate (Fig. 13.10)
Transport of neurotransmitters:
into synaptic vesicles (Fig. 13.12 & 4.6)
across the plasma membrane (Fig. 4.7)
Methods for identifying locations of neurotransmitters in the CNS (Fig. 14.1)
Lecture 31 11/16/09
GABAA receptors (Fig. 14.4) and the distribution of mRNAs encoding them (Fig. 14.3)
Distribution of NMDA and non-NMDA (AMPA) receptors (Fig. 14.5)
Cholinergic innervation of the brain (Fig. 14.6)
Noradrenergic innervation of the brain (Fig. 14.9 and 14.2)
Autonomic Nervous System
Parasympathetic and sympathetic (Handout 2.1, Fig. 16.1 and Table 16.1)
Fast and slow EPSPs in sympathetic postganglionic neurons (Fig. 16.2)
Conductance changes underlying fast v. slow EPSP.
Involvement of M-type potassium channels in slow EPSP (Fig. 16.3 and 16.4)
Lecture 32 11/18/09
Long term changes in synaptic properties
Circadian rhythm and ionotropic GABA receptors in the rat SCN (Fig. 16.12)
Exercise: What are the relative levels of [Cl-]in (and thus, of VCl) during night vs. day?
Activity-dependent changes of synapses
PNS
Neuromuscular junction
Facilitation, augmentation, depression, and post-tetanic potentiation (PTP). (Figs. 12.1 & 12.2)
PTP at the ciliary ganglion (Fig. 12.3)
CNS
LTP in the hippocampus (Figs. 12.5 & 12.6)
Some properties of NMDA receptors
Glycine is a co-transmitter, voltage sensitivity (Mg++ can block), permeability to Ca++.
Mechanism underlying LTP (Fig. 12.9)