Abstract
Purpose :
A population of perivascular cells (PVC) has been identified with a location immediately external to the vascular smooth muscle cells of retinal arterioles. These cells express immunoreactivity to a pericyte marker NG2 and give rise to processes that extend into the retina. This suggests that PVCs could play a role in neurovascular coupling in the retina. However, the anatomical basis for the connection between PVC and processes has not been characterized in detail. The aim of the present study was to establish a method for electrophysiological characterization of cells that might contribute to neurovascular coupling in the retina.
Methods :
First order porcine retinal arterioles with preserved perivascular retinal tissue were mounted in a wire myograph. A glass microelectrode (WPI, USA) with a tip resistance of 30 - 110 MOhm filled with 3 M KCl solution was implanted into the wall of retinal arterioles using an electronic micromanipulator. The microelectrode was connected to an amplifier (Electrometer 773 Duo, WPI, USA) and intracellular membrane potential was recorded.
Results :
Recordings from thirteen cells from seven arterioles showed membrane potentials ranging from -93 to -37 mV (mean -61 mV, standard error 5 mV). The frequency distribution histogram of the membrane potential values revealed two distinct peaks at -80 mV and -45 mV.
Conclusions :
Cells in the retinal arteriolar wall can be penetrated with microelectrodes for measurement of the membrane potential. Preliminary recordings suggest the existence of at least two different cell types with distinct membrane potentials in the retinal arteriolar wall. The anatomical basis for these different cell types should be characterized further by intracellular dye injection and immunohistochemistry.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.