title: Cilnidipine more highly attenuates cold pressor stress-induced platelet activation in hypertension than does amlodipine.
abstract: The clinical significance of N-type calcium channel blockade has not been fully examined. We here compared the effects of the N-type calcium channel blockers cilnidipine and amlodipine on the sympathetic nervous system and platelet function in hypertension under resting and stressed conditions. Thirty-two patients with hypertension (58+/-9 years) received cilnidipine or amlodipine for 4 weeks in this crossover study. On day 28 of each treatment, plasma levels of epinephrine (EP), norepinephrine (NEP), and beta-thromboglobulin (BTG), and EC50 of ADP-induced platelet aggregation (ADPE50) were determined at rest and after a cold pressor test. On day 29, the group receiving cilnidipine was switched to amlodipine treatment, and vice versa. At rest, the blood pressure, heart rates, EP, NEP, ADPEC50, and BTG, were similar in both treatments. After the cold pressor test, increases in EP (35+/-17 to 44+/-25 pg/ml; p<0.05) and BTG (40+/-13 to 49+/-22 ng/ml; p<0.01) and a decrease in ADPEC50 (32+/-26 to 27+/-24 micromol; p<0.05) were observed in the amlodipine treatment, but not in the cilnidipine treatment. In addition, the increase in NEP was significantly greater (p<0.05) in the amlodipine (276+/-78 to 318+/-87 pg/ml; p<0.01) than in the cilnidipine treatment (273+/-88 to 291+/-100 pg/ml; p<0.05). Cilnidipine more highly attenuates the activation of platelet function in response to cold pressor stress than does amlodipine. Attenuated activation of the sympathetic nervous system via N-type calcium channel blockade may contribute to this phenomenon.
authors.affiliation: Department of Cardiology, Teikyo University Ichihara Hospital, Japan. tomiyama@tokyo-med.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Tomiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwabara
authors.forename: C
authors.initials: C
authors.lastname: Maruyama
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Kuwata
authors.forename: T
authors.initials: T
authors.lastname: Kinouchi
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: N
authors.initials: N
authors.lastname: Doba
mesh_terms: D017311:Amlodipine / Q000627:therapeutic use*; D001794:Blood Pressure / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D003080:Cold Temperature; D018592:Cross-Over Studies; D004095:Dihydropyridines / Q000627:therapeutic use*; D004837:Epinephrine / Q000097:blood; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D015539:Platelet Activation / Q000187:drug effects*; D013312:Stress, Physiological / Q000097:blood / Q000209:etiology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D001620:beta-Thromboglobulin / Q000032:analysis
chemical_list: D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D001620:beta-Thromboglobulin; D017311:Amlodipine; C065927:cilnidipine; D009638:Norepinephrine; D004837:Epinephrine