Single injections of Met-enkephalin (ME; 27 rats) and artificial cerebrospinal fluid (ACF; 9 rats) in nucleus reticularis paragigantocellularis (PGC) and periaqueductal gray (PAG), and simultaneous conjoint PAG + PGC injections were made, and effects on facial responsiveness and caudal-trigeminal nuclear neuronal activity studied. It was found that all ME injections depressed the evoked excitatory neuronal and behavioral responses to noxious stimulation. Conjoint injections had apparently additive effects in comparison to single injection effects. Neither conjoint nor single injections had systematic effects on spontaneous neuronal activity. The ACF had no effects on any neuronal or behavioral activity.
- Nucleus reticularis paragigantocellularis
- Opiate analgesia
- Periaqueductal gray
- Trigeminal nucleus
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Behavioral Neuroscience