[Morphine self-administration by rats using a pneumatic syringe].
An apparatus for drug self-administration by rats using a pneumatic syringe was developed by Weeks. A microliter syringe operated by a pneumatic cylinder supplies an accurate volume of drug solution within one second. When coefficient of variation of infusion volume was compared among pneumatic syringe, infusion pump, and peristaltic pump, pneumatic syringe showed higher accuracy in infusion volume than the other two pumps. Since the infusion speed by a pneumatic syringe is very rapid (less than one second per infusion), the effect of infusion speed on reinforcing property of morphine was investigated. When rats self-administered 0.1, 0.3, 1.0, and 3.0 mg/kg/infusion of morphine by pneumatic syringes, the patterns of self-infusion were more stable, the number of self-infusions and the amount self-administered were larger, and a dose-response relationship was clearer in comparison with those self-infused the same doses of morphine for 5.6 seconds by infusion pumps or peristaltic pumps.
Akiyama
Y
Y
Drug Safety Research Center, Daiichi Seiyaku Co., Ltd., Tokyo, Japan.
Takayama
S
S
D000818:Animals; D004305:Dose-Response Relationship, Drug; D007260:Infusion Pumps; D008297:Male; D009020:Morphine / Q000008:administration & dosage* / Q000494:pharmacology; D009021:Morphine Dependence; D051381:Rats; D011919:Rats, Inbred Strains; D012646:Self Administration / Q000295:instrumentation*
D009020:Morphine