autonomic ganglia

Question 1

autonomic ganglia are not simply ____, are more like ___

Answer 1

relay stations - more like little brains

Question 2

convergence and divergence? para vs. symp?

Answer 2

convergence of input, divergence of output. usually less convergence and divergence with parasympathetic neurons that have more directed outflow; sympathetic has more divergence

Question 3

how many axons converge on each ganglion cell? each pregang. axon innervates?

Answer 3

7 axons converge on each ganglion cell. = convergence each preganglion axon can innervate up to 200 cell bodies = divergence.

Question 4

each neuron has a dominant input that produces ___ and then causes? what about minor inputs?

Answer 4

large fast nicotonic EPSP = cell gets to threshold = AP generation. minor inputs are subthreshold, only generate AP if activate simultaneously.

Question 5

ganglionic nAChR structure

Answer 5

5 subunits each with 4 transmembrane domains, subunits are different gene products.

Question 6

3 types of nAChR and subunit structure

Answer 6

adult muscle: 2 a1 + B1 + d + e. ganglionic: variable combos of a and B, but not a1. usually has a3. CNS/sensory neurons: a7 homopentamers

Question 7

main pathway for transmission is? but you also have?

Answer 7

fast nicotonic EPSPs, around 20 - 100ms. but you also have slow synpatic potentials

Question 8

slow synpatic potentials: 3 and their time?

Answer 8

slow muscarinic IPSP = 1s. slow muscarnic EPSP = 20 - 30 s. peptidergic late slow EPSP >1 - 5 min

Question 9

within ganglia: complex interactions?

Answer 9

between sympathetic, parasymp and sensory systems.

Question 10

chemical coding: name of type of transmission? in a single neuron you detect?

Answer 10

plurichemical transmission. upt to 8 peptides, plus NA or ACh in a single neuron.

Question 11

logical basis for peptide localization

Answer 11

they “color” the type of sympathetic output of the ganglion cell

Question 12

costa + furness: two rules that govern peptide distribution within ANS

Answer 12

neurons within same ganglion may have the same chemical codes depending on their peripheral projections. differently coded axons make connections with specific populations of post ganglionic neurons

Question 13

example of how neurons within same ganglion will have same chemical codes depending on projection

Answer 13

in superior cervical ganglion, neurons projecting to: iris have NA, NPY, dynorpin. blood vessels = NA and NPY. pilo erector muscles = NA and dynorphin. salivary and lachrymal glands = NA only.

Question 14

ex of how differently coded axons make connections w/ specific populations of postg neurons

Answer 14

in human symp gang: preganglionic axons with Enk + ACh or Enk + ACh + CGRP make contact with cholinergic sympathetic neurons. pregang with NPY and ACh make contact with noradrenergic symp neurons

Question 15

bullfrog paravertebral symp ganglia: why study it? contains?

Answer 15

simple + easy to study. contains distinc vasomotor C fiber pathway and exocrine B fiber pathway, and B + C cells are readily distinguished

Question 16

B vs. C fiber pathway (bullfrogs): type? speed? goes where?

Answer 16

C: vasomotor, slow conducting, to blood vessels. B: exocrine, faster conducting, to slime glands

Question 17

vasomotor C cells have what three synpatic potentials?

Answer 17

fast nicotinic EPSP. slow muscaranic IPSP. late slow EPSP via LHRH

Question 18

exocrine B cells: what 3 synp potentials

Answer 18

fast nicotonic EPSP. slow muscarinic EPSP. late slow EPSP via LHRH released from C fibre terminals

Question 19

bullfrong: neuropeptide action at a distance

Answer 19

pregang LHRH containing C fibers don’t contact B cells. C fiber activation will also activate B neurons

Question 20

late slow and slow EPSPs: mechanism

Answer 20

supression of M-current aka blocking the mechanism that prevents the cells from firing repetivevly: you inhibit the inhibitor

Question 21

M-current from what?

Answer 21

M-type potassium channels that open (when you depolarize symp ganglion cell). tends to hyperpolarize neuron and prevent it from firing APs

Question 22

experiment: inject of current during control vs. during EPSP

Answer 22

inject current = see AP. generate slow EPSP then give current = LOTS of APs

Question 23

durings low EPSP what happens

Answer 23

excitability increased: cells tend to fire repetitively

Question 24

experiment with ex vivo C fiber?

Answer 24

ex vivo C fiber activity: causes increase in B-cell activity via LHRH

Question 25

4 prevertebral (preaortic sympathetic) ganglia

Answer 25

celiac and superior mesenteric = solar plexus. inferior mesenteric. small ganglia of pelvic plexus

Question 26

most input to prevertebral ganglia comes from? out put?

Answer 26

comes from gut, not CNS. output to enteric ganglia rather than to gut

Question 27

instead of driving ganglion cells, what does CNS do in gut

Answer 27

CNS modulates gut prevertebral ganglion-gut reflex activity