GE Scopolamine after Saccharin

Treatment with scopolamine between

-Subjects: 24 female Sprague-Dawley rats weighing 225-250g

-4 groups (n = 6 in each):

drug/sac/lithium- drug pretreatment to attenuate effects of lithium chloride

drug/sac/sham- ensure drug does not cause an aversion

veh/sac/lithium- injection control, baseline CTA and extinction

veh/sac/sham- injection control, restraint control; no aversion, baseline preference for saccharin

-All rats water-restricted for 8 days (after 3+ days of habituation to colony room):

Day 1 = water off

Days 2 and 3 = 3 h H2O access

Days 4 and 5 = 1 h H2O access

Days 6 and 7 = 30 min H2O access

Days 8 and 9 = 10 min H2O access

-Rats weighed on day before conditioning day to determine drug dose.

-Conditioning day (10):

Rats will be injected with either drug (scopolamine, 5 mg/kg, s.c.) or saline vehicle (1 ml/kg) 30 minutes before saccharin.

All rats will receive 10-min access to a bottle of 0.125% saccharin solution in home cage.

5 minutes after saccharin, rats will be injected with either drug (scopolamine, 5 mg/kg, s.c.) or saline vehicle (1 ml/kg).

30 minutes after injection, rats are injected with 6 ml/kg of 0.15M LiCl (= 38 mg/kg).

At the end of the day, rats are given ad lib water back overnight.

-Extinction days (14+):

All rats will receive 24-hour 2-bottle access to both water and saccharin. Bottles will be refilled with fresh water or saccharin daily and weighed before and after access each day to determine consumption. The water and saccharin bottles will alternate sides in the cage each day to prevent and detect place preferences.