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Low retinal dopamine and serum prolactin levels indicate an inherited dopaminergic abnormality in BW rats

1981; Elsevier BV; Volume: 32; Issue: 5 Linguagem: Inglês

10.1016/s0014-4835(81)80003-6

1096-0007

J. P. H. Wyse, F. L. Lorscheider,

Protein Kinase Regulation and GTPase Signaling

The Bmn-wys (BW) strain of rat is affected by a complex of inherited neurological abnormalities which include retinal degeneration, reduced lactation and altered motor activity. Results from the present study suggest that these abnormalities reflect a defect in neurotransmission. The Falck-Hillarp catecholamine (CA) histofluorescence technique, together with mean densitometric scanning measurements (cm2±1 s.e.m.), demonstrated a significant (P<0·001) reduction in CA histofluorescence in the inner plexiform layer of six BW retinae (0·74±0·14) compared to that present in six control retinae (2·47±0·29). It was subsequently found that mean retinal dopamine (DA) concentration (pg/μg total protein±1 s.e.m.), measured by a sensitive CA radioenzymatic assay, was selectively and significantly (P<0·05) lower in six BW retinae (2·80±0·41) compared to four control retinae (6·30±1·60). Mean serum prolactin (Prl) levels (ng/ml±1 s.e.m.), measured by radioimmunoassay, were found to be significantly (P<0·05) lower in eight BW rats (24·7±6·1) than in eight control rats (80·3±19·4). Since Prl synthesis and release in normal rats are under inhibitory regulation by DA, it is possible that low serum Prl concentrations observed in BW rats may be the result of increased DA turnover. This possibility, in conjunction with the low retinal DA levels, leads us to conclude that an inherited dopaminergic abnormality may be the pathogenic basis for the various neurological defects displayed by BW rats.