REINFORCING PROPERTIES OF THE SUBSTANCE-P C-FRAGMENT ANALOG DIME-C7 IN CARASSIUS-AURATUS

The aim of the present study was to investigate whether two substance P (SP) fragments have reinforcing effects in Carassius auratus when th e fish were tested in a place-preference experimental model. Fish were placed in a 3-compartment box in which one compartment gives access t o two others that are not connected. The time spent in each compartmen t was recorded for 10 min in order to determine which one was preferre d. Twenty-four hours later the fish were given one of the following ip treatments: 1) group VEH (N = 12), injected with teleost saline, 2) g roup DiMe-C7 (N = 12), injected with 33 mu g/kg DiMe-C7, and 3) group SP1-7 (N = 12), injected with 167 mu g/kg SP1-7. Immediately after tre atment the fish were kept for 30 min in the compartment that was the l east preferred on the day before and this procedure was repeated for 3 days. On the fifth day the fish were retested for 10 min to determine the time spent in each compartment. Two-way analysis of variance with treatments and testing as factors indicated a main effect (P<0.0025) as well as a testing effect (P<0.009). The post-hoc Scheffe multiple c omparison test indicated that only the DiMe-C7 group presented an incr ease in the time spent in the paired compartment after treatment. We s uggest that the C-terminal fragment of SP has reinforcing effects in C arassius auratus.