Avtor/Urednik		Hankins, M; Ikeda, H
Naslov		Dopamine pathways in the outer mammalian retina - and abnormalities expressed in hereditary retinal dystrophy
Tip		članek
Vir		Zdrav Vestn
Vol. in št.		Letnik 62, št. Suppl 1
Leto izdaje		1993
Obseg		str. 33-8
Jezik		eng
Abstrakt		The dopaminergic pathway affecting rod-driven horizontal cells has been studied, both in the normal pigmented rat and the Royal College ofSurgeons (RCS) rat with hereditary retinal dystrophy during the period preceding photoreceptor loss. In the normal retinae, dopamine (2-1O microM) depolarizes horizontal cells and reduces the light response to fullfield stimulation, whilst the D1 antagonist, SCH 23390 (10 microM), hyperrpolarizes horizontal cells and enhances the fullfield light response. These results reveal an endogenous dopamine pathway, mediated by D1 receptors, which regulates horizontal cell response. In the predegenerate retina of the RCS rat, SCH 23390 had no effect on the horizontal cells, though they were depolarized by exogenous dopamine. Thus, there appears to be a significant reduction of endogenous dopamine release in these retinae, though the dopamine receptors are normal. Furthermore, SCH 23390 had no effect on horizontal cells in control retinae when applied in the presence ofmelatonin (200-500 nM). Thus, in the period preceding photoreceptor cell loss, the RCS retina expresses a functional abnormality involving dopaminergic pathways. Since the melatonin content of the RCS retina has been reported to be high, we propose that abnormalities in the dopamine/melatonin system generate a functional deficit in the retina of the RCS rat.
Deskriptorji		RETINA NEUROREGULATORS RATS, INBRED STRAINS DOPAMINE MELATONIN