Cerebral perfusion pressure (CPP) is the net pressure gradient that drives oxygen delivery to cerebral tissue. It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP). As CPP is a calculated value, MAP and ICP must be measured simultaneously. In research models, anesthetized and acute monitoring is incapable of providing a realistic picture of the relationship between ICP and MAP under physiological and/or pathophysiological conditions. For long-term monitoring of both pressures, the principle of telemetry can be used. The aim of this study was to map changes in CPP and spontaneous behavior using continuous pressure monitoring and video recording for 7 days under physiological conditions (group C - 8 intact rats) and under altered brain microenvironment induced by brain edema (group WI - 8 rats after water intoxication) and neuroprotection with methylprednisolone - MP (group WI+MP - 8 rats with MP 100 mg/kg b.w. applicated intraperitoneally during WI). The mean CPP values in all three groups were in the range of 40-60 mm Hg. For each group of rats, the percentage of time that the rats spent during the 7 days in movement pattern A (standard movement stereotype) or B (atypical movement) was defined. Even at very low CPP values, the standard movement stereotype (A) clearly dominated over the atypical movement (B) in all rats. There was no significant difference between control and experimental groups. Chronic CPP values with correlated behavioral type may possibly answer the question of whether there is a specific, universal, optimal CPP at all.

Institute of Physiology 1st Faculty of Medicine Charles University Praha 2 Czech Republic

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Hiploylee C, Colbourne F. Intracranial pressure measured in freely moving rats for days after intracerebral hemorrhage. Exp Neurol. 2014;255:49–55. doi: 10.1016/j.expneurol.2014.02.017. PubMed DOI

Guild SJ, McBryde FD, Malpas SC. Recording of intracranial pressure in conscious rats via telemetry. J Appl Physiol (1985) 2015;119:576–581. doi: 10.1152/japplphysiol.00165.2015. PubMed DOI

Kozler P, Maresova D, Pokorny J. Cytotoxic brain edema induced by water intoxication and vasogenic brain edema induced by osmotic BBB disruption lead to distinct pattern of ICP elevation during telemetric monitoring in freely moving rats. Neuro Endocrinol Lett. 2019;40:249–256. PubMed

Kozler P, Maresova D, Pokorny J. Intracranial pressure and mean arterial pressure monitoring in freely moving rats via telemetry; pilot study. Neuro Endocrinol Lett. 2019;40:319–324. PubMed

Manley GT, Fujimura M, Ma T, Noshita N, Filiz F, Bollen AW, Chan P, Verkman AS. Aquaporin-4 deletion in mice reduces brain edema after acute water intoxication and ischemic stroke. Nat Med. 2000;6:159–163. doi: 10.1038/72256. PubMed DOI

Kozler P, Pokorný J. Altered blood-brain barrier permeability and its effect on the distribution of Evans blue and sodium fluorescein in the rat brain applied by intracarotid injection. Physiol Res. 2003;52:607–614. PubMed

Clancy JJ, Caldwell DF, Villeneuve MJ, Sangiah S. Daytime sleep-wake cycle in the rat. Physiol Behav. 1978;21:457–459. doi: 10.1016/0031-9384(78)90109-9. PubMed DOI

Simasko SM, Mukherjee S. Novel analysis of sleep patterns in rats separates periods of vigilance cycling from long-duration wake events. Behav Brain Res. 2009;196:228–236. doi: 10.1016/j.bbr.2008.09.003. PubMed DOI PMC

Eftekhari S, Westgate CSJ, Johansen KP, Bruun SR, Jensen RH. Long-term monitoring of intracranial pressure in freely-moving rats; impact of different physiological states. Fluids Barriers CNS. 20209;17:39. doi: 10.1186/s12987-020-00199-z. PubMed DOI PMC

Lassen NA. Cerebral blood flow and oxygen consumption in man. Physiol Rev. 1959;39:183–238. doi: 10.1152/physrev.1959.39.2.183. PubMed DOI

McCann UG, 2nd, Schiller HJ, Carney DE, Kilpatrick J, Gatto LA, Paskanik AM, Nieman GF. Invasive arterial BP monitoring in trauma and critical care: effect of variable transducer level, catheter access, and patient position. Chest. 2001;120:1322–1326. doi: 10.1378/chest.120.4.1322. PubMed DOI

Wilson MH. Monro-Kellie 2.0: The dynamic vascular and venous pathophysiological components of intracranial pressure. J Cereb Blood Flow Metab. 2016;36:1338–1350. doi: 10.1177/0271678X16648711. PubMed DOI PMC

Kofke WA, Rajagopalan S, Ayubcha D, Balu R, Cruz-Navarro J, Manatpon P, Mahanna-Gabrielli E. Defining a Taxonomy of Intracranial Hypertension: Is ICP More Than Just a Number? J Neurosurg Anesthesiol. 2020;32:120–131. doi: 10.1097/ANA.0000000000000609. PubMed DOI PMC

Pickard JD, Czosnyka M. Management of raised intracranial pressure. J Neurol Neurosurg Psychiatry. 1993;56:845–858. doi: 10.1136/jnnp.56.8.845. PubMed DOI PMC

Godoy DA, Murillo-Cabezas F, Suarez JI, Badenes R, Pelosi P, Robba C. “THE MANTLE” bundle for minimizing cerebral hypoxia in severe traumatic brain injury. Crit Care. 2023;27:13. doi: 10.1186/s13054-022-04242-3. PubMed DOI PMC

Kozler P, Maresova D, Pokorny J. Study of locomotion, rearing and grooming activity after single and/or concomitant lesions of central and peripheral nervous system in rats. Neuro Endocrinol Lett. 2017;38:495–501. PubMed

Schallert T, Woodlee MT. Brain-dependent movements and cerebral-spinal connections: key targets of cellular and behavioral enrichment in CNS injury models. J Rehabil Res Dev. 2003;40(4 Suppl 1):9–17. doi: 10.1682/JRRD.2003.08.000918. PubMed DOI

Whishaw IQ, Pellis SM, Gorny B, Kolb B, Tetzlaff W. Proximal and distal impairments in rat forelimb use in reaching follow unilateral pyramidal tract lesions. Behav Brain Res. 1993;56:59–76. doi: 10.1016/0166-4328(93)90022-I. PubMed DOI

Sousa N, Almeida OF, Wotjak CT. A hitchhiker’s guide to behavioral analysis in laboratory rodents. Genes Brain Behav. 2006;(5 Suppl 2):5–24. doi: 10.1111/j.1601-183X.2006.00228.x. PubMed DOI

Alves R, Barbosa de Carvalho JG, Benedito MA. High and low rearing subgroups of rats selected in the open field differ in the activity of K+-stimulated p-nitrophenylphosphatase in the hippocampus. Brain Res. 2005;1058:178–182. doi: 10.1016/j.brainres.2005.08.005. PubMed DOI

Berridge KC, Whishaw IQ. Cortex, striatum and cerebellum: control of serial order in a grooming sequence. Exp Brain Res. 1992;90:275–290. doi: 10.1007/BF00227239. PubMed DOI

Kozler P, Herynek V, Marešová D, Perez PD, Šefc L, Pokorný J. Effect of methylprednisolone on experimental brain edema in magnetic resonance imaging. Physiol Res. 2020;69:919–926. doi: 10.33549/physiolres.934460. PubMed DOI PMC

Fantini S, Sassaroli A, Tgavalekos KT, Kornbluth J. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods. Neurophotonics. 2016;3:031411. doi: 10.1117/1.NPh.3.3.031411. PubMed DOI PMC