title: Regional differences in serotonin content in the nucleus of the solitary tract of male rats after hypovolemia produced by polyethylene glycol.
abstract: Serotonin (5-HT) has been implicated in centrally mediated compensatory responses to volume loss in rats. Accordingly, we hypothesized that slowly developing, non-hypotensive hypovolemia increases serotonin in the hindbrain nucleus of the solitary tract (NTS). We produced volume loss in adult male rats by administering hyperoncotic polyethylene glycol (PEG) and then assessed 5-HT levels in the NTS using measurements of tissue 5-HT content or 5-HT immunohistochemistry. The results show selective increases of 5-HT in the caudal NTS after PEG treatment, but no change in the primary 5-HT metabolite, 5-HIAA. Moreover, the intensity of 5-HT immunolabeled fibers in the caudal NTS was increased after PEG treatment. These findings suggest that, after PEG-induced hypovolemia, 5-HT accumulates in neural elements in the caudal NTS. We propose that this accumulation is attributable to an initial release of 5-HT that then acts at presynaptic autoreceptors to inhibit subsequent 5-HT release.
authors.affiliation: Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, 1111 West 17th St, Tulsa, OK, 74107-1898, USA.
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Curtis
authors.affiliation: Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, 1111 West 17th St, Tulsa, OK, 74107-1898, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Anderson
authors.affiliation: Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, 1111 West 17th St, Tulsa, OK, 74107-1898, USA. kath.curtis@okstate.edu.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Curtis
mesh_terms: D000818:Animals; D020896:Hypovolemia / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D011092:Polyethylene Glycols / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D017552:Solitary Nucleus / Q000378:metabolism*
chemical_list: D012701:Serotonin; D011092:Polyethylene Glycols