Extract from Calotropis procera latex activates murine macrophages.

Calotropis procera latex has long been used in traditional medicines. Extracts from C. procera latex have been reported to have various pharmacological actions, including protection from myocardial infarction, hepatoprotective action, antitumor activity, antinociceptive, and pro- and anti-inflammatory actions.

Extension of time until cardiac arrest after injection of a lethal dose of pentobarbital in the hibernating Syrian hamster.

The aim of the present study was to examine whether entry of peripherally injected drugs into the central nervous system is reduced during hibernation. When a lethal dose of pentobarbital was injected intraperitoneally, the time until cardiac arrest was significantly longer in hibernating hamsters than in active controls. The time difference was not a consequence of low body temperature or diminished circulation, because mimicking these parameters in artificial hypothermia did not prolong the time.

Central A1-receptor activation associated with onset of torpor protects the heart against low temperature in the Syrian hamster.

Body temperature drops dramatically during hibernation, but the heart retains the ability to contract and is resistant to induction of arrhythmia. Although adaptive changes in the heart prior to hibernation may be involved in the cold-resistant property, it remains unclear whether these changes are sufficient for maintaining cardiac pulsatility under an extreme hypothermic condition. We forcibly induced hypothermia in Syrian hamsters by pentobarbital anesthesia combined with cooling of the animals.