Neuropharmacology - 1

Question 1

what is Site of action

Answer 1

drug in the systemic circulation

Question 2

Routes of Administration of drug

Answer 2

intravenous injection , The Oral Route

Question 3

what are most drugs?

Answer 3

weak ACIDS or BASES

Question 4

in what form is the drug best absorbed?

Answer 4

unionised form

Question 5

what is the term used for a drug to break down into smaller particles so that it can be absorbed into the systemic circulation?

Answer 5

dissolution

Question 6

Rate of absorption also dependent on?

Answer 6

Gut motility –>
Gastric emptying modulated by:
meal size
meal composition (fat)
drugs (opioids, anticholinergics)
physiological state (position) - stressed then sower + also lying doen slows down
Migraine (gastric stasis)

Question 7

what is meant by Splanchnic blood flow
and how can it be effected?

Answer 7

blood supply to the gastrointestinal tract, liver, spleen, and pancreas.
- meal size

Question 8

what is first pass metabolism and how is it a negative?

Answer 8

metabolism that occurs before drug enters in system
- means drugs have to be administered another way

Question 9

what is the reason for failure of drugs designed for the brain?

Answer 9

blood brain barrier

Question 10

why is oral root preferred for drug administration?

Answer 10

Safest, most convenient and economical route
–> needs patient cooperation and not always bioavailable

Question 11

Large blood flow in muscles of upper arm
Route is reliable
Volume: 1-5 ml into muscle bed
Quick uptake into body (within ~ 20 minutes)
Suitable for irritant drugs
Good for depot preparations (long lasting) - oral contraceptives too
Absorption is perfusion limited (increased with exercise)
No self administration
Can be painful
Example drugs: vaccines, antipsychotic drugs, contraceptives

Question 12

what is tachyfelaxis?

Question 13

intrinsic sympathetic activity?

Question 14

What is an agonist ?

Answer 14

agonist (A) binds to receptors (R) → AR complex → (conformational change of receptor - AR* ) → Response

Question 15

for a Log concentration responce sure what do we use? dose or concentration? why?

Answer 15

dose –> we dont know the concentration only how much we gave

Question 16

so why is there a maxin=mum to the dose responce curve - 2 possible reasons?

Answer 16

becuase receptors are all filled up ==> respnce is directly proportional to the concentration of the agonist receptor complex
or
it can only contract to a certain degree. It can’t keep contracting because it can’t get any smaller.
So we may reach the top of the curve simply because the tissue is at its maximum = gut

Question 17

why is knowing the Kd of a drug helpful?

Answer 17

experimental desing - knowing what quantity of drug/agonist to use

Question 18

why cant we measure the responce of a curve and determine the ligand affinity?

Answer 18

becyase the responc eis both the affinity and efficacy

Question 19

what is tachyphylaxis? and what is the difference between tachyphylaxis and desensitization?

Answer 19

= response in that tissue gets smaller
“Tachyphylaxis typically involves rapid changes in receptor sensitivity or downstream signaling pathways in response to repeated drug exposure”

The term tachyphylaxis is used to describe desensitization that occurs

Question 20

what is an partial agonist and an inverse agonist?

Answer 20

cannot produce a full response.
So a full agonist produces a full response. - clinic use no uphoria and stops full agonist from causing euphoria

produces the opposite responce of an agonit –> reducing the response by removing the constitutive activity of the receptor.

Question 21

Do partial agonists have lower affinity?

Answer 21

no - not necessarily –> just lower EFFICACY

Question 22

whats an example of an inverse agonist?

Answer 22

the GABA receptor - gaba always preent - agonist = act like gaba = open channel more
inverse agonist = it binds to that site
and it decreases the actions of Gaba

Question 23

PAMs, AgoPAMs , NAMS?

Answer 23

positive steric modulator increases the coupling to the G protein.

Nans = do the opposite. They bind, but they reduce the effectiveness of the G protein

AgoPAMs = bind, but they also activate the receptor.

By modifying ongoing receptor activity, NAMs can fine-tune the signaling pathway and maintain the temporal pattern of receptor activation while reducing its overall intensity.

Question 24

how do we measure antagonist potency?

Answer 24

pA2 value = negative log of the molar concentration of antagonist
that reduces the effect of a known concentration of agonist
to that of half the concentration.

Question 25

what is another use of non compatitive antagonists?

Answer 25

measure amount of spare receptors. - 80% active 20% spare - eg.

Question 26

lecture 4 –>

Question 27

Anatomy of the synaptic nervous system

Answer 27

singe nerone - body in the ventral horn
axon - runs alog
neuromuscular junction (NMJ) –> synapse (uses acetylcholine)
–> there can be more branching of axon to connect eith more muscle fibres

Question 28

what is the diference between the Anatomy of the synaptic nervous system and the anatomy of the autonomic nervous system?

Answer 28

there are preganglionic and postganglionc neurons + uses ACh (acetylcoline) + but does not synpse with SKELETAL MUSCLE