Uncoupling of retinal GAP junctions depresses light signal transduction to the rat olivary pretectal nucleus (OPN)

• Autorzy: Orlowska-Feuer P. , Jeczmien J. , Lewandowski L.H.
• Języki publikacji: EN

Abstrakty

EN

BACKGROUNDANDAIMS: The olivary pretectal nucleus(OPN) is a midbrain structure well-known for the pupillary light reflex regulation. It receives strong retinal innervation from all photoreceptors types, however the main projection is from melanopsin cells. A subpopulation of OPN neurons discharges action potentials in an oscillatory manner with the period of minutes. This rhythmic firing pattern depends on the retinal input which deactivation results in neuronal rhythm abolition. Interestingly, all photoreceptors are required for the generation of oscillations in the OPN, but their engagement in driving the rhythm is determined by the lighting conditions, thus their selective activation. The aim of the present study was to verify the role of retinal gap junctions in the generation of oscillations in the OPN and in light signal transduction between the retina and the OPN. METHODS: We performed extracellular single-unit recordings in anaesthetized rats combined with the intravitreal injection of nonspecific gap junctions blocker – carbenoxolone (CBX; 5 µL; 1, 5, 20 mM) and light stimulations (10 and 160 lux) presented before and after the injection. RESULTS: Dose-dependent effects of intravitreal injections of CBX on the oscillatory rhythm in the OPN were observed, with the highest dose (20 mM) being the most effective in abolishing the rhythm. The effect was temporary, and partial recovery of oscillations was observed after 41.45±6.84 min. Moreover, such retinal desynchronization transiently depresses the sensitivity of OPN neurons to weak light stimulation (10 lux) – the responses decreased up to 70% just after the injection and gradually recovered to reach 50% of the baseline response 70 min after the injection. CONCLUSIONS: It implies that affecting retina gap junctions coupling influences rhythmic pattern of spikes generation in the OPN and at least partially disrupts light signal transmission, so one of five existing photoreceptors pathways to the higher visual brain centers.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2015
• Tom: 75
• Numer: Supl.
• Opis fizyczny: p.S96

Twórcy

autor

Orlowska-Feuer P.

• The Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland

autor

Jeczmien J.

• Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Krakow, Poland

autor

Lewandowski L.H.

• Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Krakow, Poland