Synapse and Chemical Nuerotransmission

Question 1

what is the importance of gap junction?

Answer 1

synchronization of a signal, transfer of nutritional metabolites

Question 2

what would cause gap junctions to close?

Answer 2

low pH, changes in membrane potentials and phosphorylation

Question 3

what are the 4 distinct molecular mechanisms used by cell-surface receptors for transmembrane signalling?

Answer 3

1. ligand-gated ion channels
2. receptors with intrinsic guanylyl cyclase activity
3. receptors with intrinsic or associated tyrosine kinase activity
4. G-protein-coupled receptors

Question 4

what are neurotransmitters?

Answer 4

chemicals that
are transferred
across a neuronal
synapse to either
promote or inhibit a
‘signal’

Question 5

what is acetylcholine?

Answer 5

This is predominantly an excitatory
neurotransmitter, particularly to skeletal
muscles, however, can be excitatory or
inhibitory at other sites within the CNS or
PNS

Question 6

what is dopamine?

Answer 6

an excitatory neurotransmitter, dopaminergic neurones exclusively
contain the Dopamine transporter (DAT)

Question 7

what are norepinephrine and epinephrine?

Answer 7

Both are generally excitatory neurotransmitters,
epinephrine is present at lower levels. Both norepinephrine and
epinephrine are involved in
fight-or-flight responses

Question 8

where is dopamine located?

Answer 8

mainly in the brain and a few peripheral locations

Question 9

where are norepinephrine and epinephrine located?

Answer 9

spinal cord and abdomen

Question 10

where is serotonin located?

Answer 10

predominantly located in mid brain, originating from Raphe nuclei

Question 11

what is serotonin?

Answer 11

mainly an
inhibitory neurotransmitter
exerting its effects within the
brain but it can also have
neuroendocrine effects
outside the brain e.g. altering
hormone secretion

Question 12

what is histamine?

Answer 12

either
excitatory or inhibitory,
depending on the
receptor

Question 13

where is histamine located?

Answer 13

Histaminergic neurones
are present within the
thalamus and
hypothalamus

Question 14

what are glutamatergic neurons?

Answer 14

produce glutamate, which is one of the most common excitatory neurotransmitters in the central nervous system

Question 15

what is GABA?

Answer 15

an inhibitory neurotransmitter, synthesized from glutamate by the enzyme glutamic acid decarboxylase

Question 16

what are the two types of GABA receptors?

Answer 16

GABA-A receptors are ligand-gated
channels for chloride and GABA-B receptors are GPCRs

Question 17

what is glycine?

Answer 17

a fast inhibitory
neurotransmitter

Question 18

what are barbiturates?

Answer 18

sedative drugs that promote GABAergic
signalling

Question 19

what are benzodiazapines?

Answer 19

Psychoactive drugs (also sedatives)
that promote GABAergic signalling

Question 20

effect of alcohol on neurotransmission?

Answer 20

increases both GABA and dopaminergic
signalling

Question 21

effect of cannabis on neurotransmission?

Answer 21

2-AG believed to alter the
signalling by glutamate, GABA noradrenaline,
dopamine, serotonin and acetylcholine