title: Regional differences in rat vaginal smooth muscle contractility and morphology.
abstract: The objective of this study was to define the regional differences in rat vaginal smooth muscle contractility and morphology. We evaluated circumferential segments from the proximal, middle, and distal rat vagina (n = 21) in vitro. Contractile responses to carbachol, phenylephrine, potassium chloride, and electrical field stimulation (EFS) were measured. Immunohistochemical analyses were also performed. The dose-response curves for carbachol- and phenylephrine-dependent contractions were different in the distal (P = .05, P = .04) compared to the proximal/middle regions. Adjusted for region-dependent changes in contractility, the distal vagina generated lower force in response to carbachol and higher force in response to phenylephrine. There was less force with increasing EFS frequency in the distal (P = .03), compared to the proximal/middle regions. Cholinergic versus adrenergic nerves were more frequent in the proximal region (P = .03). In summary, the results indicate that functional and morphological differences in smooth muscle and nerve fibers of the distal versus proximal/middle regions of the vagina exist.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Skoczylas
authors.forename: Zegbeh
authors.initials: Z
authors.lastname: Jallah
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Sugino
authors.forename: Suzan E
authors.initials: SE
authors.lastname: Stein
authors.forename: Andrew
authors.initials: A
authors.lastname: Feola
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshimura
authors.forename: Pamela
authors.initials: P
authors.lastname: Moalli
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D014621:Vagina / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*
chemical_list: D011189:Potassium Chloride