Table 1.

Effect of carnosine on kinetic parameters of blood platelet MAO-A activity during aging of male rats

Age groups	Age of animals (months)	Kinetic parameters of MAO-A activity
		Control (vehicle)		Carnosine (μg/kg/day, i.t. for 21 consecutive days)
		V max (ΔOD/mg protein/h)	K m (mM)	V max (ΔOD/mg protein/h)	K m (mM)
Young	4	2.04 ± 0.09	0.21 ± 0.009	2.63 ± 0.02a	0.20 ± 0.004
Aged	18	1.12 ± 0.05a	0.23 ± 0.01	1.79 ± 0.03b,d	0.21 ± 0.005
	24	0.92 ± 0.05a	0.22 ± 0.01	2.00 ± 0.06c,d	0.21 ± 0.003

Results are expressed as mean ± SEM (n = 4–6). V _max and K _m values were calculated from Line–Weaver Burk plot (Fig. 2b)

Kinetic studies were carried out using varying concentrations (0.05–0.4 mM) of serotonin

Significant differences from (a) corresponding control rats of (i) young (4 months) ^a p < 0.001, (ii) aged (18 months) ^b p < 0.001, (iii) aged (24 months) ^c p < 0.001. Significant differences from (b) corresponding carnosine treated rats (2.0 μg/kg/day, i.t.) (i) young (4 months) ^d p < 0.001