Elimination of substances from the brain parenchyma: efflux via perivascular pathways and via the blood–brain barrier

Table 7 Blood–brain permeability-surface area products (PS) from influx data and calculated blood–brain barrier efflux rate constants, k_eff,BBB for mannitol, sucrose and inulin

	PS/(10⁻² µL g⁻¹ min⁻¹)	k_eff,BBB/min⁻¹
Mannitol
Ohno et al. [591]	180	0.0090
Amtorp [592]	121	0.0061
Preston et al. [593]	72	0.0036
Sisson and Oldendorf [594]	10	0.0005
Daniel et al. [595]	49	0.0025
Preston and Haas [531] as purchased^{a, c}	68	0.0034
Purified^c	44	0.0022
Average		0.0040
s.e.m		0.0013
Sucrose
Ohno et al. [591]	40	0.002
Amtorp [592]	20	0.001
Preston et al. [593]	48	0.0024
Davson and Spaziani # [596]	22	0.0011
Reed and Woodbury [597]	5.3	0.00026
Cameron et al. # [598]	33	0.0017
Preston and Haas [531] as purchased^{a, c}	37	0.0019
Purified^c	15.3	0.00076
Smith [599]	24	0.0012
Preston and Webster 2002 [600]	11.8	0.00059
Miah et al. [532] radiolabelled^a	40	0.002
Miah et al. [532] mass spec.	4	0.0002
Average		0.0011
s.e.m		0.0002
Inulin
Ohno et al. [591]	1.44–2	0.00008
Amtorp [592]	15	0.00075
Preston et al. [593]	9	0.00045
Reed and Woodbury [597]	< ~ 0.3	0.00002
Daniel et al. [595]	6	0.0003
Smith [599]	< 1.5	0.00006
Preston and Webster [600]	3.9	0.0002
Kakee et al. [601]^b	30	0.0015
Average		0.00027
s.e.m		0.00010

The volume of distribution is assumed to be 0.2 mL g⁻¹. Italic values are excluded from calculations because ^athey are for comparison with the accompanying values or ^bit is an outlier, more than 4 st. dev. from the mean of the other values for inulin. The values for mannitol and sucrose marked ^care reported for the radiolabelled substances both as purchased and following purification to remove impurities which might be transported more rapidly (see text). The average for sucrose is significantly different from than that for mannitol, p = 0.012, and that for inulin different from that for sucrose, p = 0.01. Data obtained with rats (except # in rabbits)

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