MONOAMINES, AMINO-ACIDS AND ACETYLCHOLINE IN THE PREOPTIC AREA AND ANTERIOR HYPOTHALAMUS OF RATS - MEASUREMENTS OF TISSUE-EXTRACTS AND IN-VIVO MICRODIALYSATES

A microbore column high-performance liquid chromatography (HPLC) syste m was used to measure neurotransmitters in tissue extracts and in vivo microdialysates obtained from the preoptic area (PO) and anterior hyp othalamus (AH) of rats. The extracts contained norepinephrine, epineph rine, 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine, 5-hydroxyindol eacetic acid (5-HIAA), homovanillic acid (HVA), 5-hydroxytryptamine (5 -HT), aspartate, glutamate, GABA, acetylcholine (ACh) and choline. The microdialysates obtained from the PO and AH of freely moving rats con tained all of these substances except for norepinephrine, epinephrine, dopamine, and 5-HT. During collection of microdialysate from the PO a nd AH, core body temperature and locomotor activity were simultaneousl y measured by means of telemetry. The locomotor activity and body temp erature increased during the night. This was accompanied by increased levels of 5-HIAA. The results suggest that serotonergic neuronal mecha nisms in the PO and AH may be involved in hypothalamic regulation of s pontaneous behaviors and body temperature. (C) 1998 Elsevier Science I nc. All rights reserved.