Dysfunctional Light-Evoked Regulation of cAMP in Photoreceptors and Abnormal Retinal Adaptation in Mice Lacking Dopamine D4 Receptors

• DOI: 10.1523/jneurosci.22-06-02063.2002
• Publication Date: 2018-04-13T22:30:10Z
• Authors: Izhak Nir; Joseph M. Harrison; Rashidul Haque; Malcolm J. Low; David K. Grandy; Marcelo Rubinstein; P. Michael Iuvone
• Keywords: Dysfunctional family

Dopamine is a retinal neuromodulator that has been implicated in many aspects of physiology. Photoreceptor cells express dopamine D4 receptors regulate cAMP metabolism. To assess the effects on photoreceptor physiology, we examined morphology, electrophysiology, and regulation metabolism mice with targeted disruption receptor gene. morphology outer segment disc shedding after light onset were normal knock-out (D4KO) mice. Quinpirole, D2/D3/D4 agonist, decreased synthesis retinas wild-type (WT) but not D4KO In WT retinas, photoreceptors which functionally isolated by incubation presence exogenous glutamate, also suppressed synthesis. Despite similar inhibition synthesis, effect directly independent modulation, because it was unaffected application antagonist l -745,870. Nevertheless, compared basal formation reduced had no additional inhibitory effect. The results suggest dopamine, via receptors, normally modulates cascade couples responses to adenylyl cyclase activity cells, absence this modulation dysfunction cascade. Dark-adapted electroretinogram (ERG) However, ERG b-wave greatly during both adaptation early stages dark adaptation. Thus, affects adaptation, altering transmission from inner neurons. These findings indicate play major role regulating adaptive changing environmental illumination.