Permeability of the blood-brain barrier system to rubidium in euthermia, hibernation and hypothermia

Extension of Time until Cardiac Arrest after Injection of a Lethal Dose of Pentobarbital in the Hibernating Syrian Hamster

“…Alternatively, it is possible that transfer of the anesthetic to the CNS is reduced in hamsters during hibernation. This view would conflict with the finding in an earlier study that a hypothermic condition increases permeability of the blood brain barrier in rats [14]. This apparent conflict can be explained by the assumption of operation of a hibernationspecific mechanism that limits access of peripherally injected drugs to the CNS.…”

Extension of Time until Cardiac Arrest after Injection of a Lethal Dose of Pentobarbital in the Hibernating Syrian Hamster

“…Alternatively, it is possible that transfer of the anesthetic to the CNS is reduced in hamsters during hibernation. This view would conflict with the finding in an earlier study that a hypothermic condition increases permeability of the blood brain barrier in rats [14]. This apparent conflict can be explained by the assumption of operation of a hibernationspecific mechanism that limits access of peripherally injected drugs to the CNS.…”

Inhibition of NMDA‐type glutamate receptors induces arousal from torpor in hibernating arctic ground squirrels (Urocitellus parryii)

“…1988), were equally as effective at inducing arousal. Evidence suggests that the blood–brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood–brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK‐801‐induced arousal is further supported by failure of direct administration of MK‐801 by icv injection at a dose of up to 200 μg to induce arousal.…”

“…The conclusion that the site of MK-801 action lies outside of the CNS, or within circumventricular organs, is supported by the finding that systemic administration of AP5 which does not cross the blood-brain barrier (Tonkiss and Rawlins 1991) and MK-801 which crosses the blood-brain barrier (Ozyurt et al 1988;Park et al 1988), were equally as effective at inducing arousal. Evidence suggests that the blood-brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood-brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK-801-induced arousal is further supported by failure of direct administration of MK-801 by icv injection at a dose of up to 200 lg to induce arousal.…”

Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers

“…Extreme temperatures affect the BBB permeability, with an association between hyperthermia and BBB disruption in rats [69,70]. In the case of hypothermia, artificial induction in rats, as well as natural hibernation in ground squirrels, increase BBB permeability [71]. The mechanisms and consequences of increased BBB permeability during the lowered body temperatures caused by hibernation and torpor remain poorly understood.…”

Extension of Time until Cardiac Arrest after Injection of a Lethal Dose of Pentobarbital in the Hibernating Syrian Hamster

“…Alternatively, it is possible that transfer of the anesthetic to the CNS is reduced in hamsters during hibernation. This view would conflict with the finding in an earlier study that a hypothermic condition increases permeability of the blood brain barrier in rats [14]. This apparent conflict can be explained by the assumption of operation of a hibernationspecific mechanism that limits access of peripherally injected drugs to the CNS.…”

Inhibition of NMDA‐type glutamate receptors induces arousal from torpor in hibernating arctic ground squirrels (Urocitellus parryii)

“…1988), were equally as effective at inducing arousal. Evidence suggests that the blood–brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood–brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK‐801‐induced arousal is further supported by failure of direct administration of MK‐801 by icv injection at a dose of up to 200 μg to induce arousal.…”

“…The conclusion that the site of MK-801 action lies outside of the CNS, or within circumventricular organs, is supported by the finding that systemic administration of AP5 which does not cross the blood-brain barrier (Tonkiss and Rawlins 1991) and MK-801 which crosses the blood-brain barrier (Ozyurt et al 1988;Park et al 1988), were equally as effective at inducing arousal. Evidence suggests that the blood-brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood-brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK-801-induced arousal is further supported by failure of direct administration of MK-801 by icv injection at a dose of up to 200 lg to induce arousal.…”

Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers

“…Extreme temperatures affect the BBB permeability, with an association between hyperthermia and BBB disruption in rats [69,70]. In the case of hypothermia, artificial induction in rats, as well as natural hibernation in ground squirrels, increase BBB permeability [71]. The mechanisms and consequences of increased BBB permeability during the lowered body temperatures caused by hibernation and torpor remain poorly understood.…”

Extension of Time until Cardiac Arrest after Injection of a Lethal Dose of Pentobarbital in the Hibernating Syrian Hamster

“…Alternatively, it is possible that transfer of the anesthetic to the CNS is reduced in hamsters during hibernation. This view would conflict with the finding in an earlier study that a hypothermic condition increases permeability of the blood brain barrier in rats [14]. This apparent conflict can be explained by the assumption of operation of a hibernationspecific mechanism that limits access of peripherally injected drugs to the CNS.…”

Inhibition of NMDA‐type glutamate receptors induces arousal from torpor in hibernating arctic ground squirrels (Urocitellus parryii)

“…1988), were equally as effective at inducing arousal. Evidence suggests that the blood–brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood–brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK‐801‐induced arousal is further supported by failure of direct administration of MK‐801 by icv injection at a dose of up to 200 μg to induce arousal.…”

“…The conclusion that the site of MK-801 action lies outside of the CNS, or within circumventricular organs, is supported by the finding that systemic administration of AP5 which does not cross the blood-brain barrier (Tonkiss and Rawlins 1991) and MK-801 which crosses the blood-brain barrier (Ozyurt et al 1988;Park et al 1988), were equally as effective at inducing arousal. Evidence suggests that the blood-brain barrier remains intact during torpor (Wells 1972), so it is unlikely that AP5 reached NMDAR within the CNS except at circumventricular organs where fenestrations in the blood-brain barrier allow for communication between the blood and CNS. The interpretation that a CNS site, excluding circumventricular organs, is not involved in MK-801-induced arousal is further supported by failure of direct administration of MK-801 by icv injection at a dose of up to 200 lg to induce arousal.…”

Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers

“…Extreme temperatures affect the BBB permeability, with an association between hyperthermia and BBB disruption in rats [69,70]. In the case of hypothermia, artificial induction in rats, as well as natural hibernation in ground squirrels, increase BBB permeability [71]. The mechanisms and consequences of increased BBB permeability during the lowered body temperatures caused by hibernation and torpor remain poorly understood.…”