title: Cerebrospinal fluid dynorphin-converting enzyme activity is increased by voluntary exercise in the spontaneously hypertensive rat.
abstract: The activity in cerebrospinal fluid (CSF) of dynorphin-converting enzyme (DCE) has been studied after voluntary exercise in the spontaneously hypertensive (SH) rat. The exercise consisted of spontaneous running in wheels for 4-5 weeks and the average running distance during the last two weeks was 4.0 km/24h. CSF samples were obtained under anaesthesia from the cisterna magna after penetration of the atlanto-occipital membrane. DCE transforms the members of the dynorphin family of opioid peptides into Leu-enkephalin-Arg6. In the present investigation a radioimmunoassay was used for quantitation of Leu-enkephalin-Arg6 release from dynorphin A1-17 and dynorphin B1-13. The rats that were running had a DCE activity (vs. both substrates) in CSF that was approximately 6-12 times higher than in animals not given the running opportunity. A statistically significant correlation between the two prodynorphin-derived substrate peptides was found in terms of DCE activity. We therefore propose that a single enzyme activity may be responsible for the hydrolysis of dynorphin B1-13 and dynorphin A1-17. Furthermore, a significant correlation was also found between running activity and DCE activity 12-14 h before the CSF was withdrawn. Besides measurement of DCE activity by radioimmunoassay, the formation of Leu-enkephalin-Arg6 was identified by reversed-phase micro-column liquid chromatography and plasma desorption mass spectrometry. The experiment shows that voluntary exercise affects opioid peptidergic mechanisms.
authors.affiliation: Department of Pharmaceutical Biosciences, University of Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Persson
authors.forename: I
authors.initials: I
authors.lastname: Jónsdóttir
authors.forename: P
authors.initials: P
authors.lastname: Thorén
authors.forename: C
authors.initials: C
authors.lastname: Post
authors.forename: F
authors.initials: F
authors.lastname: Nyberg
authors.forename: P
authors.initials: P
authors.lastname: Hoffmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002853:Chromatography, Liquid; D003546:Cysteine Endopeptidases / Q000134:cerebrospinal fluid*; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010805:Physical Conditioning, Animal; D005082:Physical Exertion / Q000502:physiology*; D011863:Radioimmunoassay; D051381:Rats; D011918:Rats, Inbred SHR
chemical_list: D003546:Cysteine Endopeptidases; C063078:dynorphin converting enzyme