Models used in Screen of analgesic

1. BAUCHI STATE UNIVERSITY GADAU
FACULTY OF BASIC MEDICAL SCIENCE
DEPARTMENT OF PHARMACOLOGY
COURSE CODE: PCL 4106
COURSE TITLE: ETHNOPHARMACOLOGY
A PRESENTATION ON MODELS USED IN SCREENING
OF ANALGESIC
GROUP 1

2. INTRODUCTION
Pain is a term used for an uncomfortable sensation
as a result of CNS activation.
Pain can also be define as unpleasant sensory and
emotional sensation associated with actual or
potential tissue damage (by international
association for the study of pain)
Nociceptors:- they are peripheral terminals of the
afferent fibres arrived around the injury nerve.
while Nociception is the process of communicating
the brain about pain.

3. INTRODUCTION cont...
TYPES OF PAIN
1. Acute pain
2. Chronic pain
3. Neuropathic pain
4. Nociceptive pain
5. Redicular pain

4. INTRODUCTION cont...
ANALGESIC
Analgesic is any member of the group of drug used
to achieve analgesia (relief from pain) which may be
from arthritis, surgery, injury, toothache, headache,
menstrual cramps etc
TYPES OF ANALGESICS
• Narcotic Analgesic (act in the CNS)
• Non Narcotic Analgesic (act peripherally)

5. SCREENING MODELS FOR
ANALGESIC
• IN-VIVO
• IN-VITRO
IN-VIVO MODELS
1. Models using Thermal stimuli
2. Models using Electrical stimuli
3. Models using Mechanical stimuli
4. Models using Chemical stimuli

6. SCREENING MODELS FOR
ANALGESIC cont...
1. Models using Thermal stimuli
Hot plate method
Tail flick model (using radiant heat)
Pain state models using cold stimuli
- Cold tail flick test
- Cold ethonol tail flick test
2. Models using Electrical stimuli
Electrical stimulation of the tail
Electrical stimulation of the tooth pulp
Monkey shock titration test

7. SCREENING MODELS FOR
ANALGESIC cont...
3. Models using mechanical stimuli
Haffner's tail clip method
Randall selitto test
4. Models using chemical stimuli
Formalin test
Writhing test
Stimulation of hollow organs

8. SCREENING MODELS FOR
ANALGESIC cont...
IN-VITRO MEDELS
1. 3H-Naloxone binding assay
2. Opoids receptors binding assay
3. Cannabinoids binding assay
4. Inhibition of Enkephalinase

9. HOT PLATE MODEL
MATERIALS USED
• Animal required; Albino mice
• Chemical required; compound to be tested
• Equipment required; Hot plate at 55-66°C, stop
watch

10. HOT PLATE MODEL cont...
PROCEDURE
Mice (18-22g) are used
Temperature of 55-66°C is maintained (of the hot
plate)
The animal is then placed on the hot plate and watch
out for the time until either licking or jumping occur,
then record
The latency is recorded before and after 20, 60 and
90mins after the administration of standard or test
compound

11. HOT PLATE MODEL cont...
EVALUATION
• The prolongation of latency time between the test,
standard and control animals are compared
• Using various doses, ED50 value can be calculated

12. THANKS YOU FOR LISTENING

13. GROUP MEMBERS