title: Ocular hypotension induced by intravitreally injected C-type natriuretic peptide.
abstract: The purpose of the study is to determine if intravitreal injection of c-type natriuretic peptide (CNP) affects intraocular pressure (IOP), aqueous humor dynamics and guanosine 3',5'-cyclic monophosphate (cGMP) concentration in the aqueous humor of the rabbit eye. Also we investigated whether CNP-like immunoreactivities (CNP-LI) were present in porcine aqueous humor and whether CNP-LI were detected in rabbit and porcine ciliary body. The IOP was measured after intravitreal injection of 2 pmol approximately 20 nmol CNP into rabbit eyes. Aqueous humor dynamics (aqueous humor flow, outflow facility, and uveoscleral outflow) and cGMP concentration in the aqueous humor were determined at approximately 6 hr after CNP injection. The CNP concentration in aqueous was measured by radioimmunoassay in porcine eye, and CNP-LI were detected with a monoclonal antibody in porcine and rabbit eyes. Intravitreally injected CNP caused IOP reduction in a dose-dependent manner (P<0.0001) and the maximum effect was observed at 4 approximately 6 hr. CNP increased total outflow facility by approximately 35%, but did not affect aqueous humor flow or uveoscleral outflow. The cGMP concentration in the aqueous of CNP-treated eyes was about 4- to 14-fold higher than that in the contralateral untreated eyes. CNP concentration in aqueous was about 2-fold higher than that in plasma, and CNP-LI were found in non-pigmented epithelium of the ciliary body of both rabbit and porcine eyes. CNP may play an important role in the regulation of IOP.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takashima
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: M S
authors.initials: MS
authors.lastname: Haque
authors.forename: T
authors.initials: T
authors.lastname: Igaki
authors.forename: H
authors.initials: H
authors.lastname: Itoh
authors.forename: K
authors.initials: K
authors.lastname: Nakao
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: N
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000737:chemistry / Q000502:physiology; D006152:Cyclic GMP / Q000378:metabolism; D007150:Immunohistochemistry; D007429:Intraocular Pressure / Q000187:drug effects; D020098:Natriuretic Peptide, C-Type; D015814:Ocular Hypotension / Q000139:chemically induced*; D011506:Proteins / Q000009:adverse effects*; D011817:Rabbits; D013552:Swine; D013997:Time Factors
chemical_list: D011506:Proteins; D020098:Natriuretic Peptide, C-Type; D006152:Cyclic GMP