Table I.

Morphometric analysis of synaptic vesicle types in the 3 and 9 years old rhesus monkey DCN.

	Area ± SEM	Major Axis ± SEM	Minor Axis ± SEM	Size ± SEM	Circularity
3 years old
Round synaptic vesicles
LR	2013.3 ± 9.9**	54.9 ± 1.2	46.2 ± 1.2	50.5 ± 1.1**	0.9
N= 5; Nsv= 100
MR	1027.6 ± 25.8**	38.5 ± 0.5	33.5 ± 0.5	36.0 ± 0.4**	0.9
N= 5; Nsv= 109
SR	743.5 ± 8.2**	34.0 ± 0.2	28.0 ± 0.2	30.8 ± 0.1**	0.9
N= 17; Nsv= 413
Non-round synaptic vesicles
LF	1587.5 ± 80.2**	61.5 ± 2.0	32.2 ± 1.1	47.0 ± 1.2**	0.6
N= 8; Nsv= 147
SF	1123.1 ± 32.2**	50.6 ± 0.9	28.1 ± 0.5	39.1 ± 0.5**	0.7
N= 9; Nsv= 167
SP	804.0 ± 30.1**	42.1 ± 0.8	24.4 ± 0.7	32.5 ± 0.5**	0.7
N= 7; Nsv= 123
9 years old
Round synaptic vesicles
LR	1966.3 ± 59.6**	52.5 ± 0.8	47.3 ± 0.7	49.9 ± 0.7**	0.9
N= 4; Nsv= 80
MR	1329.1 ± 56.2**	43.1 ± 0.8	39.0 ± 0.1	41.1 ± 0.9**	0.9
N= 6; Nsv= 125
SR	882.6 ± 30.3**	35.3 ± 0.6	31.7 ± 0.6	32.1 ± 1.2**	0.9
N= 14; Nsv= 280
Non-round synaptic vesicles
LF	1003.2 ± 18.5**	52.0 + 0.5	24.5 + 0.3	38.3 + 0.3**	0.7
N= 5; Nsv= 147
SF	899.0 ± 43.7**	45.7 ± 0.7	24.5 ± 0.7	35.1 ± 0.7**	0.7
N= 5; Nsv= 112
SP	690.0 ± 23.2**	37.1 ± 0.7*	23.5 ± 0.4	30.3 ± 0.4**	0.7
N= 5; Nsv= 110

N= number of synaptic endings analyzed; Nsv= number of synaptic vesicles analyzed

^**P < 0.05