Spiperone (hydrochloride)

Spiperone hydrochloride (Spiroperidol hydrochloride) is a selective dopamine D₂ receptor (K_i values of 0.06 nM, 0.6 nM, 0.08 nM, ~350 nM, ~3500 nM for D₂, D₃, D₄, D₁ and D₅ receptors, respectively) and 5-HT_2A/5-HT_1A receptor (K_is of 1 nM/49 nM) antagonist. Spiperone hydrochloride is also a selective α1B-adrenoceptor antagonist. Spiperone hydrochloride activates calcium-activated chloride channel (CaCC). Antipsychotic and anti-inflammatory activities^{[1][2][3][4][5]}. In Vitro: Spiperone is a potent intracellular Ca²⁺ enhancer (EC₅₀=9.3 μM) and stimulates intracellular Ca²⁺ through a protein tyrosine kinase-coupled phospholipase C-dependent pathway, which results in increased secretion of Cl^- in Calu-3 and CFBE41o^- cell monolayers^[2].
Spiperone significantly decreases the production of nitric oxide in lipopolysaccharide-stimulated BV-2 microglia cells, primary microglia and primary astrocyte cultures. Spiperone also significantly inhibits nitric oxide production in ATP-stimulated primary microglia cultures. Spiperone markedly decreases the production of TNF-α in BV-2 microglia cells. Spiperone attenuates the expression of inducible nitric oxide synthase and proinflammatory cytokines such as IL-1β and TNF-α at mRNA levels in BV-2 microglia cells^[3]. In Vivo: Spiperone (1.5 mg/kg; intraperitoneal injection; on days 1, 3, 6, 7, and 13-21; C57Bl/6 mice) treatment reduces infiltration of the alveolar interstitium and alveolar ducts with inflammatory cells and prevents the growth of the connective tissue in the parenchyma of Bleomycin lungs^[6].