RESUMO
Dopamine (0.5-100 muM) as well as apomorphine (1-100 muM) were found to be potent stimulators of adenylate cyclase in homogenates of rabbit retina. When compared with the dopamine-effect at 10 muM, half-stimulation was also obtained in response to noradrenaline or adrenaline, whereas isoprenaline or phenylephrine were ineffective. Furthermore, the dopamine-induced production of cyclic AMP wab blocked by chloropromazine and haloperidol. These data would suggest the occurrence of a specific "dopamine receptor" in the retina of the rabbit.
Assuntos
Adenilil Ciclases/metabolismo , Apomorfina/farmacologia , Dopamina/farmacologia , Retina/enzimologia , Animais , Clorpromazina/farmacologia , AMP Cíclico/biossíntese , Antagonistas de Dopamina , Relação Dose-Resposta a Droga , Epinefrina/farmacologia , Haloperidol/farmacologia , Técnicas In Vitro , Isoproterenol/farmacologia , Fentolamina/farmacologia , Coelhos , Receptores de Droga , Estimulação Química , Frações Subcelulares/enzimologiaRESUMO
Three groups of insulin-dependent diabetics (I without clinical signs of peripheral neuropathy; II with peripheral neuropathy; III with neuropathy involving the peripheral and autonomous nervous system) and investigated for optic and trigeminal neuropathy (corneal sensitivity). In all groups, but with increasing frequency from group I to III, signs of optic neuropathy (constriction of visual fields with good central vision, impaired colour vision, decreased visually evoked responses and corneal sensitivity) were noted. The frequent observation of impaired colour vision deserves particular attention, since the patient's interpretation of tape-tests for glucosuria depends upon it.