Neurochemistry (2)

Question 1

who discovered neurotransmitters and how

Answer 1

loewi
he used frogs and stimulated the vagus nerve in one frog to produce ACh and then took the ACh and put it on the heart of another frog. the chemical made the heart change speeds

Question 2

what is a type 1 synapse and what function are they associated with

Answer 2

asymmetrical; EPSP

Question 3

what is a type 2 synapse and what function are they associated with

Answer 3

symmetrical; IPSP

Question 4

where are neurotransmitters produced

Answer 4

amino acids/amines are produced in the presynaptic terminal

peptides are produced in the soma and transported down the axons

Question 5

what are the steps leading to neurotransmitter release from pre synaptic terminals

Answer 5

action potential is reached and Ca2+ channels open, Ca2+ released the vesicles, the vesicles dock to the presynaptic membrane, the pre synaptic membrane opens (exocytosis) and the neurotransmitter is released into the synapse

Question 6

what are two ways that neurotransmitters are deactivated when they are released in the synapse

Answer 6

reuptake and degradation

Question 7

what determines the effects of a specific neurotransmitter

Answer 7

the receptors that the neurotransmitters bind to

Question 8

what are the different subtypes of neurotransmitter receptors

Answer 8

ionotropic: transmitter-gated ion channels
metabotropic: g-protein coupled receptor

Question 9

what are the four major types of NT receptors

Answer 9

ionotropic, metabotropic, enzyme-linked, intracellular

Question 10

what is the general protein structure of ionotropic receptors

Answer 10

5 protein subunits where each subunit contains 4 alpha helicies

Question 11

what is the general protein structure of metabotropic receptors

Answer 11

single polypeptide with 7 membrane spanning regions

Question 12

what are the different kinds of receptors based on location

Answer 12

heteroreceptors: respond to NT different than the ones contained in its synaptic vesicles
autoreceptors: respond to NT released from its own synaptic vesicles

Question 13

what are the 7 criteria for determining if a substance is a neurotransmitter

Answer 13

1. found in pre synaptic terminal
2. has enzymes for synthesis
3. released from presynaptic terminal
4. action on a postsynaptic neuron
5. has postsynaptic receptors
6. undergoes deactivation
7. has predictable effects

Question 14

what is the synthetic/metabolic pathway for GABA

Answer 14

glutamine –> (glutaminase) –> glutamate –> (glutamic acid decarboxylase) –> GABA

Question 15

what is synthetic/metabolic pathway for the catecholamine neurotransmitters

Answer 15

phenylalanine 
(phenylalanine hydroxylase)
tyrosine
(tyrosine hydroxylase)
dopa
(aromatic l-amino acid decarboxylase)
dopamine
(dopamine beta hydroxylase)
norepinephrine
(phenylethtanolamine-N-methyltransferase)
epinephrine

Question 16

what are retrograde messengers

Answer 16

synthesized in post synaptic elements and flows post to pre

Question 17

which neurotransmitters are retrograde messengers

Answer 17

endocannabinoids and soluble gases

Question 18

what is dale’s principle

Answer 18

a neuron releases the same neurotransmitter at all its synapses

Question 19

what are the three main components of a signaling system

Answer 19

molecular signal, receptor molecule, target effector/response molecule

Question 20

what are the main effector cascades

Answer 20

g-proteins, second messengers, nuclear messengers

Question 21

how do g-proteins activation regulate second messengers

Answer 21

number of things available (ex. ATP that is in cell to use)

Question 22

what is the function of activated beta/gamma subunits

Answer 22

remain on membrane

Question 23

which g-protein subunit is mainly responsible for the production of cyclic nucleotide second-messengers

Answer 23

alpha subunit
alpha stimulatory will increase production
alpha inhibitory will decrease production of cyclic AMP
can also interact with adenyl cyclase in the membrane to produce cAMP from ATP

Question 24

what are the targets of second messengers

Answer 24

protein kinases (adding phosphate groups) through phosphorylation can effect gene expression

Question 25

how can the intracellular signaling cascades induce changes in neural functions

Answer 25

phosphorylation by the kinases

Question 26

what is the signaling mediated by the cyclic nucleotide cascades

Answer 26

adenyl cyclase, pka, pkc

Question 27

what is the signaling mediated by the lipid cascade

Answer 27

phospholipase C, PIP2, IP3, DAG

Question 28

what do protein kinases do

Answer 28

add phosphate group (target tyrosine, serine, threonine)

Question 29

what do protein phosphatases do

Answer 29

remove phosphate groups

Question 30

how is Ca regulated in neurons

Answer 30

voltage-gated ion channels