Autoregulation of optic-disk oxygen tension*

ثبت نشده
چکیده

A micro-oxygen sensor was used to monitor the optic-disk oxygen tension in vivo in the cat. The perfusion pressure of the eye, defined as the systemic arterial blood pressure minus the intraocular pressure, was decreased. This was accomplished both by lowering the systemic arterial blood pressure by increasing the expiratory resistance and by elevating the intraocular pressure. The result of lowering the perfusion pressure of the eye was an initial decrease in the optic-disk oxygen tension and then a return to normal within approximately one minute. This autoregulation of the optic-disk oxygen tension was decreased by hypoxia and eliminated by hypercapnia. It was concluded that this autoregulation is a physiologic adjustment for homeostasis of the optic-disk tissue.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Autoregulation of optic-disk oxygen tension.

A micro-oxygen sensor was used to monitor the optic-disk oxygen tension in vivo in the cat. The perfusion pressure of the eye, defined as the systemic arterial blood pressure minus the intraocular pressure, was decreased. This was accomplished both by lowering the systemic arterial blood pressure by increasing the expiratory resistance and by elevating the intraocular pressure. The result of lo...

متن کامل

Oxygen and blood flow: players in the pathogenesis of glaucoma

UNLABELLED The increase of IOP in POAG is due an increased resistance of aqueous outflow through the trabecular meshwork (TM). The exact mechanisms leading to the corresponding changes in the TM are not yet known. We know, however, that all risk factors for arteriosclerosis are also risk factors for an increase in IOP. RESULTS The association between IOP increase and these factors is relative...

متن کامل

Pressure compliance of the optic nerve head in low tension glaucoma.

Twenty eyes of 10 healthy subjects, 11 eyes of seven patients with low tension glaucoma, and three eyes of three patients with ischaemic optic neuropathy were investigated. Visual evoked responses were recorded under stepwise artificially increased intraocular pressures. The results of the visual evoked response recording (pressure compliance test) allow a clear distinction to be made between h...

متن کامل

Optic nerve oxygen tension: effects of intraocular pressure and dorzolamide.

AIM To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide. METHODS Domestic pigs were used as experimental animals. Oxygen tension was measured by means of a polarographic electrode in the vitreous...

متن کامل

Myocardial oxygen tension determines the degree and pressure range of coronary autoregulation.

Experiments were designed to separate effects of myocardial oxygen tension and oxygen consumption on coronary autoregulation. The approach was to measure coronary hemodynamic and metabolic responses to decreases in perfusion pressure during interventions that altered the balance between myocardial oxygen supply and demand. Studies were conducted in anesthetized heart-blocked dogs with the left ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2005