Contribution of Ca²⁺-Dependent Cl⁻ Channels to Norepinephrine-Induced Contraction of Femoral Artery Is Replaced by Increasing EDCF Contribution during Ageing

Table 3

Maximal norepinephrine-induced contraction and acetylcholine-induced relaxation of femoral arteries isolated from adult and aged WKY and SHR.

Parameters	Adult WKY; (6 months); (𝑛=6)	Aged WKY; (12 months); (𝑛=7)	Adult SHR; (6 months); (𝑛=6)	Aged SHR; (12 months); (𝑛=9)	WKY; (20 months); (𝑛=16)
Norepinephrine-induced (10^−4 mol/L) maximal contraction (mN/mm)	5.26 ± 0.84	5.30 ± 0.64	8.25 ± 0.32^a	10.41 ± 0.70^a,b	6.79 ± 0.20
Acetylcholine-induced (3.10^−8 mol/L) relaxation (%)	53 ± 3	47 ± 6	55 ± 4	37 ± 4^a,b	18 ± 4^c
Acetylcholine-induced (3.10^−8 mol/L) wall tension decrease (mN/mm)	−2.70 ± 0.36	−2.02 ± 0.41	−4.37 ± 0.70^(a)	−4.18 ± 0.55^a	−0.98 ± 0.22^c
Acetylcholine-induced relaxation (%)*	85 ± 4	82 ± 5	67 ± 4^a	70 ± 2	79 ± 2
Acetylcholine-induced wall tension decrease (mN/mm)*	−4.37 ± 0.65	−3.49 ± 0.44	−5.30 ± 0.38	−8.04 ± 0.84^a,b	−4.70 ± 0.23

Data are presented as mean ± S.E.M.; ^a𝑃<0.05 versus aged-matched WKY; ^b𝑃<0.05 versus adult SHR; ^c𝑃<0.05 versus WKY; ^(a)represents borderline significance 𝑃<0.08. *Maximal acetylcholine-induced relaxations were achieved in femoral arteries of WKY at the concentration 10⁻⁶ mol/L and in femoral arteries of SHR at the concentration 3.10⁻⁶ mol/L.