Pharmacological and molecular evidence for dopamine D1 receptor expression by striatal astrocytes in culture

✍ Scribed by Patrizia Zanassi; Mayra Paolillo; Alessandra Montecucco; Enrico V. Avvedimento; Sergio Schinelli

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 195 KB
• Volume: 58
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(19991115)58:4<544::aid-jnr7>3.0.co;2-9

✦ Synopsis

The neurotransmitter dopamine (DA) at a 10 µM concentration elicited a stimulation of intracellular cyclic AMP (cAMP) accumulation in cultured astrocytes derived from embryonic rat striatum. This accumulation was partially blocked by the ␤-adrenergic receptors antagonist propranolol, mimicked by the D 1 agonist SKF 38393 and by the mixed D 1 /D 2 agonist apomorphine. A regional heterogeneity in the magnitude of dopamine-induced cAMP accumulation was observed in cultured astrocytes obtained from different brain areas. The maximum effect was observed in striatal astrocytes, a lower effect in cortical astrocytes, and no increase was detected in cerebellar astrocytes.

Reverse transcription-polymerase chain reaction (RT-PCR) coupled to

Southern blot hybridization demonstrated that striatal astrocytes express only D 1 receptor mRNA and Western blot analysis confirmed the expression of the D 1 receptor protein in striatal astrocytes. In contrast to what found in neurons, the D 1 -dependent cAMP formation in striatal astrocytes is partially reduced by pertussis toxin (PTX) treatment. The stimulation of D 1 receptors or the activation of adenylyl cyclase by forskolin led to an increase of cytosolic and nuclear protein kinase A (PKA) catalytic activity. The presence of dopamine D 1 receptors in cultured striatal astrocytes suggests a role of dopamine in the regulation of cellular processes in striatal astrocytes.