TY  - JOUR
AU  - Arboit, Alberto
AU  - Krautwald, Karla
AU  - Angenstein, Frank
TI  - Hemodynamic responses in the rat hippocampus are simultaneously controlled by at least two independently acting neurovascular coupling mechanisms
JO  - Journal of cerebral blood flow & metabolism
VL  - 44
IS  - 6
SN  - 0271-678X
CY  - London
PB  - Sage
M1  - DZNE-2024-00300
SP  - 896 - 910
PY  - 2024
AB  -  We combined electrical perforant pathway stimulation with electrophysiological and fMRI recordings in the hippocampus to investigate the effects of neuronal afterdischarges (nAD) on subsequent fMRI BOLD signals in the presence of isoflurane and medetomidine. These two drugs already alter basal hemodynamics in the hippocampus, with isoflurane being mildly vasodilatory and medetomidine being mildly vasoconstrictive. The perforant pathway was stimulated once for 8 seconds with either continuous 20 Hz pulses (continuous stimulation) or 8 bursts of 20 high-frequency pulses (burst stimulation). Burst stimulation in the presence of medetomidine elicited long-lasting nAD that coincided with a brief positive BOLD response and a subsequent long-lasting decrease in BOLD signals. Under isoflurane, this stimulation elicited only short-lasting nAD and only a short-lasting decline in BOLD signals. In contrast, continuous stimulation under isoflurane and medetomidine caused a similar duration of nAD. Under isoflurane, this caused only a sharp and prolonged decline in BOLD signals, whereas under medetomidine, again, only a brief positive BOLD response was elicited, followed by a shorter and moderate decline in BOLD signals. Our results suggest that nAD simultaneously activate different neurovascular coupling mechanisms that then independently alter local hemodynamics in the hippocampus, resulting in an even more complex neurovascular coupling mechanism.
KW  - Animals
KW  - Neurovascular Coupling: physiology
KW  - Neurovascular Coupling: drug effects
KW  - Isoflurane: pharmacology
KW  - Hippocampus: physiology
KW  - Hippocampus: drug effects
KW  - Hippocampus: blood supply
KW  - Medetomidine: pharmacology
KW  - Male
KW  - Magnetic Resonance Imaging
KW  - Rats
KW  - Hemodynamics: drug effects
KW  - Hemodynamics: physiology
KW  - Electric Stimulation
KW  - Anesthetics, Inhalation: pharmacology
KW  - Rats, Wistar
KW  - Perforant Pathway: physiology
KW  - Perforant Pathway: drug effects
KW  - Cerebrovascular Circulation: physiology
KW  - Cerebrovascular Circulation: drug effects
KW  - BOLD-fMRI (Other)
KW  - dentate gyrus (Other)
KW  - in vivo electrophysiology (Other)
KW  - negative BOLD response (Other)
KW  - neuronal afterdischarges (Other)
LB  - PUB:(DE-HGF)16
C2  - pmc:PMC11318394
C6  - pmid:38087890
DO  - DOI:10.1177/0271678X231221039
UR  - https://pub.dzne.de/record/268721
ER  -