Beta‐adrenergic receptor subtypes in the basal ganglia of patients with Huntington's chorea and Parkinson's disease

Abstract

The density of [125I]iodo-cyanopindolol binding to beta-1 and beta-2 adrenergic receptors was studied in post mortem basal ganglia samples of Huntington's chorea and Parkinson's disease patients using autoradiography. Whereas no significant changes were observed in sections from Parkinson's and Huntington's chorea grade 2 patients, a nearly complete loss of beta-1 binding sites was observed in the basal ganglia of Huntington patients at later stages of the disease. The concentration of beta-2 receptors was increased by a factor 2 in the posterior putamen of all choreic cases. These results are consistent with the view that beta-1 receptors are predominantly located on a subpopulation of neurons which degenerate at late stages of Huntington's chorea, while beta-2 receptors are present mainly on glial elements.

Astrocytic β 2 -adrenergic receptors mediate hippocampal long-term memory consolidation

“…Notably, the knockdown of the astrocyte-selective virus was more robust (about 50%) than that of the neuron-selective virus (about 20%), as is consistent with a more abundant β 2 AR binding codistribution with astrocytes than with neurons and with previous literature suggesting higher expression of β 2 AR in glia (18,(21)(22)(23)). …”

“…The expression and distribution of β 2 ARs on different cell types is not clear; although some studies suggest that β 2 ARs are expressed mainly in glia (18,(21)(22)(23), others report that they are found on both astrocytes and neurons (20). To determine the selective functional contribution of astrocytic and/or neuronal β 2 AR in long-term memory formation, we used cell-specific virusmediated knockdown of the receptors.…”

“…However, in addition to being expressed in pre-and postsynaptic compartments of neurons, βARs are also found in other cell types, particularly in astrocytes (18)(19)(20)(21). More specifically, it has been suggested that β 2 ARs in the nervous system are expressed predominantly in glia (18,(21)(22)(23), whereas β 1 ARs are found primarily in neurons, at synaptic junctions (18,22,23). This suggestion raises the question of which βAR subtype (β 1 AR or β 2 AR) and which βAR-expressing cells mediate hippocampal memory consolidation.…”

Behavioral and Cellular Modulation of l-DOPA-Induced Dyskinesia by β-Adrenoceptor Blockade in the 6-Hydroxydopamine-Lesioned Rat

“…Thus, in recent years, there has been increased interest in the use of adrenergic compounds to prevent or reduce LID (Colosimo and Craus, 2003;Brotchie, 2005). Although most of the research has focused on ␣-adrenergic compounds (Savola et al, 2003;Rommelfanger and Weinshenker, 2007;, the striatum contains a high density of ␤ARs (Rainbow et al, 1984), which are preserved in PD patients (Waeber et al, 1991). These receptors represent a unique therapeutic target for LID because ␤AR blockade prevents drug-induced facilitation of DA release in intact and DA-depleted animals, which may blunt downstream signaling abnormalities associated with LID (Reisine et al, 1982;Goshima et al, 1991).…”

β1-Adrenergic Receptor Association with PSD-95

“…The tissue distributions of the three receptors are distinct: ␤ 2 AR is highly expressed in many tissues, ␤ 3 AR is expressed at high levels only in adipose tissue, and ␤ 1 AR is expressed at high levels in the heart and brain and lower levels elsewhere (1). In the brain, ␤ 1 AR exhibits a predominantly neuronal expression pattern, whereas ␤ 2 AR is expressed mainly in glial cells (2)(3)(4). ␤ 1 AR is thus considered to be the "synaptic" ␤-adrenergic receptor, because electrophysiological experiments with specific antagonists demonstrate that ␤-adrenergic modulation of hippocampal neuronal activity exhibits a ␤ 1 AR-like pharmacological profile (5)(6)(7).…”