Munoz Jl

New ocular micromanipulator for measurements of retinal and vitreous physiologic parameters in the mammalian eye

A new ocular micromanipulator for introducing a microelectrode into the mammalian eye is described. Included is a technical description of the device, incorporating arched tracks and DC motors to provide for angular motion around a scleral entrance point. Applications for in vivo measurements of local PO2 in the retina and vitreous of miniature pigs and cats are shown. The new design features of this micromanipulator allow for smooth microelectrode movements over large retinal areas, facilitating the rapid collection of data in many different areas of the retina and vitreous.

Quartz micropipettes for intracellular voltage microelectrodes and ion-selective microelectrodes.

We find that quartz is better than borosilicate glass as a material for micropipettes for certain microelectrode applications, including ion-selective microelectrodes of the liquid membrane type. Details are given of a graphite heating element that can be mounted on a standard microelectrode puller and used for making quartz micropipettes. A novel method of silanizing micropipettes is described. Experience with a novel miniature beveller that is fitted on a microscope stage is reported.

Extracellular Potassium Change in the Rat Adenohypophysis: An Indicator of Neurohypophyseal-Adenohypophyseal Communication

It has been generally thought that hypothalamic releasing and inhibiting factors are secreted from nerve terminals of the median eminence into long portal vessels, and transported in plasma toward the anterior pituitary gland. Scanning electron microscopy of pituitary vascular casts revealed, however, that the median eminence, the posterior lobe, and the anterior lobe were interconnected by portal vessels (Page and Bergland, 1977). Further, numerous compounds with anterior lobe hormone-releasing and -inhibiting activity have been identified in the posterior lobe. Thus, posterior lobe compounds may reach the anterior lobe, as suggested by Porter et al. (1977), and modulate adenohypophyseal hormone secretions; alternatively, adenohypophyseal hormones may reach the posterior lobe (Page and Bergland, 1977).