Table 4.

Cerebrovascular Relaxation Pathways with Development

Variable	Fetus	Newborn	Adult	Reference
Intrinsic tone at 40 mmHg with endothelium intact (Mouse; %)		21±3 (210)	10±1	[106]
A-23187-Induced Relaxation (%)	35 (35)		100	[245]
Constriction to indomethacin at 40 mmHg (Mouse)		12±1 (46)	26±1	[106]
Constriction to L-NAME at 40 mmHg (Mouse)		17±1 (49)	35±2	[106]
pD2 of SNAP-Induced Relaxation	6.3±0.1		5.9±0.1	[246]
eNOS Relative Abundance	3.1±0.2 (135)		2.3±0.2	[247]
eNOS abundance (ng eNOS · mg protein−1)*	29±3 (263)		11±2	[248]
Maximum eNOS Specific Activity Slope NO (10−12 M)·eNOS (10−6 g)·min−1	3.8±0.5b (67)		5.7±1.0	[248]
eNOS abundance in microvessels (% newborn value)++		100 (36)	280±30	[249]
eNOS specific activity (nmol NO · μg eNOS−1 · min−1)*	97±36 (55)		177±44	[248]
Slope of relation of eNOS specific activity to fluid shear stress (nmol NO · μg eNOS−1 · min−1 · dyne−1·cm2 −1)*	2.9±0.1 (43)		6.8±0.1	[248]
Basal eNOS activity in microvessels (14C-citriline incorporation, cpm · mg protein−1)++		~3,500±200 (47)	~7,500±400	[249]
sGC abundance (% that in adult kidney)		0.37±0.6 (276)	0.17±0.03	[250]
sGC abundance (ng · mg protein−1)†	7.1±0.9 (132)		5.4±1.5	[251]
sGC specific activity (pmol · μg sCG−1 · min−1)†	60±2c (35)		171±19	[251]
sGC specific activity (pmol · cGMP−1 · mg−1 · min−1)		3.1±0.31 (214)	1.45±0.08	[250]
sGC activity, Vmax as determined by cGMP formation (pmol cGMP · mg protein−1 · min−1)	4.48±1.13 (954)		0.47±0.13	[252]
sGC abundance (ng sGC · mg protein−1)	17.6± 1.6a (1036)		1.7±0.3	[252]
Basal cGMP (10−9 M·10−3 protein−1)	3.3±0.5b (194)		1.7±0.2	[253]
Basal cGMP (10−6 M)*		0.59±0.11 (536)	0.11±0.02	[254]
cGMP Synthesis rate (10−6 M·1 cell water−1·min−1)*		0.31 ±0.06b (207)	0.15 ±0.04	[254]
cGMP synthesis rate (pmol cGMP · mg protein−1 · min−1)	29.5±5.6b (356)		8.3±1.4	[251]
cGMP-induced relaxation with 8-pCPT-cGMP (% maximal)†	99.2±0.8 (111)		89.3±4.6	[251]
cGMP Degradation (10−6 M·1 cell water−1·min−1)*		106±6c (136)	78±6	[254]
cGMP (pm · mg protein−1)		1.0±0.1 (333)	0.3±0.1	[253]
cGMP (10−9 M·10−3 g Soluble Protein)	0.35±0.1			[250]
cGMP (10−9 M·sGC (10−6 g)·min−	145±20 (−)			[250]
ΔpD2 for 5-HT-induced contraction with 8-pCPT-cGMP*	To 6.30±0.08 from 6.72±0.02		NSC	[47]
Δ pD2 for 5-HT calcium sensitivity ΔTension · Δ [Ca2+]i (%)*	To 176±27 from 128±17b		NSC	[47]
Δ pD2 for K+-induced contraction with 8-pCPT-cGMP in α-toxin permeabilized vessels*	−0.4±0.1b		NSC	[47]
Δ maximum 5-HT-induced rise in [Ca2+]i with 8-pCPT-cGMP (%)*	To 64±9 (150) from 88±6c		To 82±7 from 98±14	[47]
Basal ratio of cGMP to cAMP		~6	~3	[255]
Prostaglandin I2 NO	> <			[154, 155]
COX-2 in microvessels (% newborn value)++		100	128±10	[249]
Basal COX activity in microvessels (PG production, pg · μg protein−1)++		2.2±0.4	2.2+-0.5	[249]
COX activity in microvessels (PGE2 production, pg · μg protein−1)++		1.6±0.3 (133)	1.2±0.3	[249]
Hypoxic-Induced CBF (% Control)	+43			[256]
Hypoxic-Induced CBF (% Control)	+50			[257]
Above with L-NAME inhibition	+			[256]
Carbon Monoxide as measured by [HbCO]	2 to 3† (200 to 300)		1	[258]

Values are mean ± SE of 5 or more in each group;

Values in parentheses represent % of adult values;

Significantly different from adult value:

^aP<0.001;

^bP<0.01;

^cP<.05;

^†Basilar artery;

^*CCA;

⁺⁺Pigs; NSC, no significant change