PURPOSE. To determine the roles of dopamine D2 receptors (D2Rs) and dopamine D1 receptors (D1Rs) in the inhibition of form-deprivation myopia (FDM) by the nonselective dopamine agonist apomorphine (APO) in D2R-knockout (D2R-KO) and D1R-KO mice. METHODS.Retinal layer thicknesses and electroretinograms (ERGs) were analyzed in KO mice and in D2R and D1R antagonist-treated mice. D2R-KO or D1R-KO mice and wild-type (WT) littermates were subjected to form deprivation during postnatal weeks 5 to 8. Both groups were intraperitoneally injected daily with either APO (5 lg/g body weight) dissolved in 1 lg/ lL ascorbic acid or vehicle alone. Refraction, vitreous chamber depth (VCD), and axial length (AL), among other parameters, were measured prior to and at the end of the treatment period.RESULTS. The retinal layer thicknesses and ERGs in KO mice were similar to those treated with D2R and D1R antagonists. APO administration in WT mice inhibited the development of FDM by approximately 80%. FDM in D2R-KO mice was inhibited approximately 50% compared with WT mice and was further inhibited by APO to a level similar to that in APO-treated WT mice. FDM development in D1R-KO mice was similar to that in WT mice and was not affected by APO administration. The changes in VCD and AL were consistent with refraction data.CONCLUSIONS. In mice, APO-mediated FDM inhibition was abolished by D1R KO but not D2R KO. This indicates the specificity of D1Rs for the pharmacologic inhibitory effect of APO on FDM and a nonessential role of D2Rs in this process in mice.

In pigmented guinea pigs, D1R activation inhibited, whereas D2R activation enhanced, FDM. These results closely mirror previous findings in albino animals and offer further evidence that DA and its cognate receptors affect refractive error regulation in guinea pigs.

IntroductionBrucellosis is a systemic disease that exists prevalently in clinical manifestations. The symptoms present in organs such as the eyes (in ocular brucellosis) can lead to misdiagnosis or even failure to diagnose. Metagenomic Next-Generation Sequencing (mNGS), a high-throughput sequencing approach, could be applied for the detection of microorganisms.Case PresentationA 57-year-old female with acute right-eye vision loss, treated with clindamycin and dexamethasone sodium phosphate for 1.5 months, was difficult to diagnose using regular methods. mNGS was utilized for the aqueous fluid from the patient, and Brucella melitensis was identified. The inflammation was treated with 3 months of antibiotherapy. However, even with specific medicine and surgery, the vision remained poor because severe ocular conditions last for a long time.ConclusionIt suggests that brucella should still be a probable pathogen in endophthalmitis despite its low incidence in non-epidemic areas. Moreover, mNGS can achieve early diagnosis and timely treatment for difficult-to-diagnose ocular infections.