Pharmacology

1. 1
Expt No- 9 Date- 24-9-2019
Porsolt's Forced Swim Test (Animal Model of Depression)
Aim- To study effect of ethanol on duration of immobility in Porsolt's forced swim test in rats.
Theory- Ethanol shares several pharmacological effects including sedative/hypnotic/ motor
inco-ordinating, anxiolytic and anticonvulsant actions with GABAA receptor modulators like
benzodiazepines and barbiturates. Acute administration of ethanol exhibits antidepressant like
action which is potentiated by muscimol a GABAA receptor agonist and blocked by bicuculline,
a GABAA receptor antagonist.
Requirements- Rats, Ethanol, glass cylinder.
Procedure- The rats were subjected to pre-test session for 15min in a glass cylinder (21 x 12 x
12cm) containing water up to 9cm maintained at 25 + 2oC. 24h later, the animals were treated
intraperitoneally either with vehicle or ethanol (2.5g/kg of 20% v/v) and each animal was again
forced to swim in similar environment for a period of 6min in a test session and immobility time
was recorded. The rat was judged immobile if it ceased struggling and remained floating

2. 2
motionless in water making only those movements necessary to keep its head above water.
Reduction in the duration of immobility was considered as antidepressant like effect.
Observation table- Effect of ethanol on latency to immobility and duration of immobility in
forced swim test in rats-
Gp I- Normal vehicle
SN Wt in gm Treatment – water 2ml/kg bw ip Latency to immobility in sec Duration of immobility in sec
1 129 0.25 300 342
2 132 0.26 300 345
3 131 0.26 290 341
4 130 0.26 310 348
5 129 0.25 295 339
6 128 0.25 305 342
SD 300+ 7.07 342.83+ 3.19
Gp II-Ethanol treated-The density of 20% ethanol is 0.969g/ml 2.5g = 2.58ml (2.58ml/kg bw ip)
SN Wt in gm Treatment -Ethanol 2.58ml/kg
20%v/v ip
Latency to immobility in sec Duration of immobility in sec
1 118 0.30 175 300
2 130 0.33 180 240
3 119 0.30 176 296
4 129 0.33 179 242
5 117 0.30 182 302
6 131 0.33 178 240
SD 178.33 + 2.58*** 270+ 32.20 ***
Statistical analysis was done by student t test. The latency to immobility shown by group II rats
( p value less than 0.0001) was considered to be extremely statistically significant (178.33 +
2.58) when it is compared to group I rats (300+ 7.07 sec),
The duration of immobility shown by group II rats ( p value equals to 0.0003) was considered to
be extremely statistically significant (270+ 32.20) when it is compared to group I rats (342.83+
3.19).
Report- The present results provide evidence for an antidepressant-like action of ethanol as the
ethanol ingested rats were shown a significant decrease in the latency of immobility and
duration of immobility when compared to vehicle treated normal rats (group I).