Age-related changes in the turnover rates of D1-dopamine receptors in the retina and in distinct areas of the rat brain

Giorgi, Osvaldo; Pibiri, Maria G.; Toso, Roberto Dal; Ragatzu, Giuseppe

doi:10.1016/0006-8993(92)90646-q

Cited by 21 publications

(3 citation statements)

References 35 publications

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“…Whilst changes in postsynaptic sensitivity are more likely, we cannot exclude the possibility that a reduction in DAT activity may enhance exogenous ligand access to the DA receptor. Interestingly, comparative studies of both striatal and retinal DA receptor density in young and old rats have shown that the density of D1 receptors increases in senile animals, largely as a result of a reduction in the rate of receptor degradation (Giorgi et al, 1992). Interestingly, whilst the D1 receptors were found to be increased in the senile rat retina, the level of DA-dependent adenylate cyclase was shown to be unaffected (Porceddu et al, 1990).…”

Section: Discussionmentioning

confidence: 99%

Functional dopamine deficits in the senile rat retina

Hankins

2000

Vis Neurosci

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The activity of the endogenous retinal dopamine (DA) pathway has been examined in the pigmented rat using retinas obtained from normal adult (approximately 3 months) and senile adults (approximately 24 months) using an in vitro electrophysiological approach. By comparing the pharmacological sensitivity of the horizontal cells (HCs) to exogenous DA, a D1 receptor antagonist (SCH 23390) and a DA-transport inhibitor (nomifensine), it is suggested that there is a functional deficit in the endogenous DA activity in the senile retina. Cells recorded from retinae obtained from senile animals are more sensitive to exogenous DA, whilst the senile retina is insensitive to SCH 23390. In addition, nomifensine was effective in potentiating subthreshold DA applications, but only in the normal adult retina. The data may suggest that endogenous DA release upon the HCs and selective re-uptake are suppressed in these retinae. These functional deficits also appear to be associated with changes in the receptive fields of the HCs, suggesting there is a corresponding deficit in spatial processing at the outer plexiform layer (OPL) of the senile rat.

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Section: Discussionmentioning

confidence: 99%

Functional dopamine deficits in the senile rat retina

Hankins

2000

Vis Neurosci

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“…Joyce et al, 1986;Giorgi et al, 1987;Hyttel et al, 1987;Morgan et al, 1987;Han et al, 1989;Morelli et al, 1990;Rinne et al, 1990;Murray and Waddington, 1991;Antononi et al, 1993). This reduction in dopamine receptor density has been attributed to the loss of receptor-containing neurons as well as to reduced receptor synthesis in the surviving neurons during ageing (Mesco ef al., 1991;Giorgi et al, 1992). Interestingly, the decrease in dopamine receptors number in the striatum starts at 11-12 months of age in the rat (Morelli et al, 1990).…”

Section: Dopamine-glutamate-gaba Interactions In the Striatum Of The mentioning

confidence: 99%

Dopamine‐Glutamate‐GABA Interactions and Ageing: Studies in the Striatum of the Conscious Rat

Porras

Mora

1995

Eur J of Neuroscience

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The effects of apomorphine, a D1-D2 dopamine receptor agonist, on the extracellular concentrations of glutamate and GABA were investigated in the striatum of young, middle-aged and aged rats. In vivo intracerebral perfusions were undertaken in the conscious rat using a concentric push-pull cannula system. Amino acid concentrations in samples were determined by HPLC with fluorometric detection. Apomorphine produced a concentration-related rise in striatal glutamate and GABA concentrations in young rats. Maximal increases were obtained at 20 microM apomorphine, and concentrations reached 184 and 191% of the basal value for glutamate and GABA respectively. Apomorphine failed to produce similar increases in glutamate concentration in middle-aged and aged rats. Apomorphine, at 10 microM, also failed to produce an increase in GABA concentration in the aged rats. However, at 20 microM apomorphine produced increases in GABA concentration in middle-aged and aged rats similar to those produced in young rats. These data are indicative of a change in threshold for GABA release induced by dopamine receptor stimulation in the aged rat. These results indicate that an interaction among dopamine, glutamate and GABA exists in the striatum of the rat, and that this type of interaction deteriorates with age.

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“…Animal models using rats (Giorgi et al, 1992) and chicks (Zawilska et al, 2004) have revealed that D1-like dopamine receptors present in the retina.…”

Section: The Action Of Dopamine and The Eyementioning

confidence: 99%

Vitamin D in Dry Eye and Myopia

Yang¹

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Age-related changes in the turnover rates of D1-dopamine receptors in the retina and in distinct areas of the rat brain

Cited by 21 publications

References 35 publications

Functional dopamine deficits in the senile rat retina

Functional dopamine deficits in the senile rat retina

Dopamine‐Glutamate‐GABA Interactions and Ageing: Studies in the Striatum of the Conscious Rat

Vitamin D in Dry Eye and Myopia

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