Visual evoked potentials and nociceptive thresholds in high and low self-stimulators.
Tail flick latencies (TFL) were examined in order to distinguish between rats from genetically high (HI) and low (LO) self-stimulation lines (LC2-HI and LC2-LO). In addition, slow secondary negative wave (SNW) of the visual evoked potential, which is considered to be a sensitive index of normal and pharmacologically-induced behavioral arousal, was analysed. Small, albeit statistically significant enhancement of SNW was obtained in LO rats. Unlike LO animals, HI rats gained in SNW amplitude during repeated photic stimulation. The difference between the lines was highly significant. TFL assessment yielded slightly reduced (NS) values for HI rats. However, when TFL and SNW data were compared it appeared that TFL vary as a function of SNW amplitude in LO but not in HI rats, (r = 0.9). SNW may be employed as a predictor of the nociceptive threshold in rats.
D000818:Animals; D001931:Brain Mapping; D004723:Endorphins / Q000502:physiology; D005074:Evoked Potentials, Visual; D005260:Female; D007026:Hypothalamic Area, Lateral / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D012653:Self Stimulation / Q000502:physiology*; D012684:Sensory Thresholds; D013045:Species Specificity
D004723:Endorphins; D009638:Norepinephrine