Labetalol

Labetalol (AH5158) is an orally available, selective α1-adrenergic recepto and non-selective β-adrenergic receptor competitive antagonist. Labetalol is an antihypertensive molecule that partially crosses the blood-brain barrier and has little effect on cardiac output. Labetalol can be used in the study of cardiovascular diseases, such as hypertension during pregnancy^[1][2][3]. In Vitro:Labetalol exhibits greater affinity for the β-adrenergic sites on guinea pig cardiac and lung membranes (IC₅₀=0.8 and 4.0 μM, respectively)^[1].
Labetalol has an affinity for the α-adrenergic binding site on rabbit uterine membranes (IC₅₀=15 μM). Labctalol has a 19-fold greater binding affinity for the β-binding site in cardiac membranes than for the α-binding site in uterine membranes^[1].
In Vivo:Labetalol (0.63-6.3 mg/kg; intravenous injection; single dose) preferentially blocks β-adrenergic responses at low doses in anesthetized dogs, and significantly blocks α-adrenergic responses at high doses (6.3 mg/kg)^[1].
Labetalol (10 mg/kg; subcutaneous injection; twice daily; 10 days) significantly increases hypothalamic α1 receptor binding and elevates the ratio of norepinephrine metabolites MHPG/NA in neonatal Wistar rats, but does not cause long-term changes in receptor density in adulthood^[2].
Labetalol (10 mg/kg; ih) crosses the blood-brain barrier and reaches 2.1 μg/g tissue level in the brain of 10-day-old rats 90 minutes after injection^[2].
Labetalol (5.0 mg/kg; ip) attenuates circulating IL-1β and IL-6 in tail-shock stressed rats^[3].