title: Dorsal hand vein responses to the α₁-adrenoceptor agonist phenylephrine do not predict responses to the α₂-adrenoceptor agonist dexmedetomidine.
abstract: Significant inter-individual variability exists in responses of human dorsal hand veins to activation of α-adrenoceptors. Simultaneous graded infusions of the α₁- and α₂-adrenoceptor agonists phenylephrine (3.66-8000 ng/min) and dexmedetomidine (0.0128-1000 ng/min) were given into dorsal veins of both hands and responses of 75 subjects were analyzed to assess whether a subject's sensitivity to phenylephrine (ED(50)) predicts his sensitivity to dexmedetomidine. Individual ED(50) estimates of dexmedetomidine and phenylephrine ranged between 0.06-412 and 14.2-7450 ng/min and exhibited only a weak positive relationship (r² =0.074, P=0.018). Finger temperature, body mass index, age and phenylephrine sensitivity together accounted for about 30% of dexmedetomidine ED(50) variation (r² =0.315, P<0.001). The large inter-individual variability observed in the responses of dorsal hand veins to both α₁- and α₂-adrenoceptor agonists is not explained by some common factors; instead, dorsal hand vein responsivity is separately determined for both receptor mechanisms.
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.
authors.forename: Jussi P
authors.initials: JP
authors.lastname: Posti
authors.forename: Laura
authors.initials: L
authors.lastname: Valve
authors.forename: Saku
authors.initials: S
authors.lastname: Ruohonen
authors.forename: Juha
authors.initials: J
authors.lastname: Akkila
authors.forename: Mika
authors.initials: M
authors.lastname: Scheinin
authors.forename: Amir
authors.initials: A
authors.lastname: Snapir
mesh_terms: D058646:Adrenergic alpha-1 Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology*; D013696:Temperature; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology; D014680:Veins / Q000187:drug effects; D055815:Young Adult
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D058647:Adrenergic alpha-2 Receptor Agonists; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D020927:Dexmedetomidine