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Release of ATP in the central nervous system during systemic inflammation: real-time measurement in the hypothalamus of conscious rabbits.

Gourine AV, Dale N, Llaudet E, Poputnikov DM, Spyer KM, Gourine VN - J. Physiol. (Lond.) (2007)

Bottom Line: Application of the ATP receptor antagonists pyridoxal-5'-phosphate-6-azophenyl-2',4'-disulphonic acid, Brilliant Blue G or periodate oxidized ATP dialdehyde to the site of ATP release in the anterior hypothalamus markedly augmented and prolonged the febrile response.These data indicate that during the development of the systemic inflammation, ATP is released in the anterior hypothalamus to limit the magnitude and duration of fever.This release may also have a profound effect on the hypothalamic control of other physiological functions in which ATP and related purines have been implicated to play modulatory roles, such as food intake, hormone secretion, cardiovascular activity and sleep.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK. a.gourine@ucl.ac.uk

ABSTRACT
Receptors for extracellular ATP (both ionotropic and metabotropic) are widely expressed in the CNS both in neurones and glia. ATP can modulate neuronal activity in many parts of the brain and contributes to the central nervous control of several physiological functions. Here we show that during the systemic inflammatory response the extracellular concentrations of ATP increase in the anterior hypothalamus and this has a profound effect on the development of the thermoregulatory febrile response. In conscious rabbits we measured ATP release in real time with novel amperometric biosensors and monitored a marked increase in the concentration of ATP (4.0 +/- 0.7 microm) in the anterior hypothalamus in response to intravenous injection of bacterial endotoxin - lipopolysaccharide (LPS). No ATP release was observed in the posterior hypothalamus. The release of ATP coincided with the development of the initial phase of the febrile response, starting 18 +/- 2 min and reaching its peak 45 +/- 2 min after LPS injection. Application of the ATP receptor antagonists pyridoxal-5'-phosphate-6-azophenyl-2',4'-disulphonic acid, Brilliant Blue G or periodate oxidized ATP dialdehyde to the site of ATP release in the anterior hypothalamus markedly augmented and prolonged the febrile response. These data indicate that during the development of the systemic inflammation, ATP is released in the anterior hypothalamus to limit the magnitude and duration of fever. This release may also have a profound effect on the hypothalamic control of other physiological functions in which ATP and related purines have been implicated to play modulatory roles, such as food intake, hormone secretion, cardiovascular activity and sleep.

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ATP biosensors and their placements in the rabbit hypothalamus A, scheme of the sensor assembly and calibration curve of the ATP biosensor. An expanded portion of the sensor is shown to indicate the enzymatic biolayer. Note that this biolayer completely surrounds the tip of the Pt wire. Calibration curve of the ATP biosensor demonstrates linearity of ATP detection in concentrations from 1 to 50 μm. B, schematic showing the placement of the sensors in the anterior hypothalamus of the rabbit. A dual recording configuration of ATP or adenosine sensor placed upon one side of the hypothalamus along with a  or inosine sensor that was placed in an equivalent position on the other side of the hypothalamus was used (see main text for details). C, histological identification of the sensor placements in the anterior (left) and posterior (right) hypothalamus. 3V, third cerebral ventricle; AH, anterior hypothalamic area; f, fornix; LH, lateral hypothalamic area; M, mammillary nuclei; MRe, mammillary recess of the third ventricle; OX, optic chiasm; SuM, supramammillary area. Arrows indicate track of the sensor.
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fig01: ATP biosensors and their placements in the rabbit hypothalamus A, scheme of the sensor assembly and calibration curve of the ATP biosensor. An expanded portion of the sensor is shown to indicate the enzymatic biolayer. Note that this biolayer completely surrounds the tip of the Pt wire. Calibration curve of the ATP biosensor demonstrates linearity of ATP detection in concentrations from 1 to 50 μm. B, schematic showing the placement of the sensors in the anterior hypothalamus of the rabbit. A dual recording configuration of ATP or adenosine sensor placed upon one side of the hypothalamus along with a or inosine sensor that was placed in an equivalent position on the other side of the hypothalamus was used (see main text for details). C, histological identification of the sensor placements in the anterior (left) and posterior (right) hypothalamus. 3V, third cerebral ventricle; AH, anterior hypothalamic area; f, fornix; LH, lateral hypothalamic area; M, mammillary nuclei; MRe, mammillary recess of the third ventricle; OX, optic chiasm; SuM, supramammillary area. Arrows indicate track of the sensor.

Mentions: Rabbits were anaesthetized with a mixture of ketamine hydrochloride (45 mg kg−1, s.c.) and xylazine hydrochloride (10.0 mg kg−1, s.c.) with additional ketamine (20 mg kg−1s.c.) administered every 30 min if necessary. A miniature temperature-sensitive telemetry transmitter (model E-mitter, Minimitter, Sunriver, OR, USA) was implanted into the abdominal cavity of each animal for continuous monitoring of Tb. Then the head of the rabbit was placed in a David Kopf stereotaxic apparatus and two 20-gauge guide cannulae (Plastics One, Roanoke, VA, USA) were implanted either bilaterally into the anterior hypothalamus (stereotaxic co-ordinates: 0.5 mm rostral to bregma, 2.5 mm lateral to midline) or bilaterally into the posterior hypothalamus (2.5 mm caudal to bregma, 2.5 mm lateral to midline) according to the atlas of Sawyer et al. (1954). Each guide cannula was lowered 8 mm from the cortical surface so that the tip was positioned 6 mm dorsal to the desired recording/microinjection sites. Two small screws were placed into the skull, and the cannula was secured in place by dental acrylic. The guide cannula was closed with a dummy cannula that extended from the tip of the guide cannula by ∼1 mm. After surgery, rabbits were housed one per cage, were given penicillin and lidocaine and were allowed to recover for at least 7 days before any experiment. At the end of the experiment the animals were killed humanely by an overdose (200 mg kg−1) of pentobarbitone sodium injected intraperitoneally (i.p.), the brains were removed and the locations of the recording and injection sites were confirmed histologically (Fig. 1C).


Release of ATP in the central nervous system during systemic inflammation: real-time measurement in the hypothalamus of conscious rabbits.

Gourine AV, Dale N, Llaudet E, Poputnikov DM, Spyer KM, Gourine VN - J. Physiol. (Lond.) (2007)

ATP biosensors and their placements in the rabbit hypothalamus A, scheme of the sensor assembly and calibration curve of the ATP biosensor. An expanded portion of the sensor is shown to indicate the enzymatic biolayer. Note that this biolayer completely surrounds the tip of the Pt wire. Calibration curve of the ATP biosensor demonstrates linearity of ATP detection in concentrations from 1 to 50 μm. B, schematic showing the placement of the sensors in the anterior hypothalamus of the rabbit. A dual recording configuration of ATP or adenosine sensor placed upon one side of the hypothalamus along with a  or inosine sensor that was placed in an equivalent position on the other side of the hypothalamus was used (see main text for details). C, histological identification of the sensor placements in the anterior (left) and posterior (right) hypothalamus. 3V, third cerebral ventricle; AH, anterior hypothalamic area; f, fornix; LH, lateral hypothalamic area; M, mammillary nuclei; MRe, mammillary recess of the third ventricle; OX, optic chiasm; SuM, supramammillary area. Arrows indicate track of the sensor.
© Copyright Policy
Related In: Results  -  Collection

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fig01: ATP biosensors and their placements in the rabbit hypothalamus A, scheme of the sensor assembly and calibration curve of the ATP biosensor. An expanded portion of the sensor is shown to indicate the enzymatic biolayer. Note that this biolayer completely surrounds the tip of the Pt wire. Calibration curve of the ATP biosensor demonstrates linearity of ATP detection in concentrations from 1 to 50 μm. B, schematic showing the placement of the sensors in the anterior hypothalamus of the rabbit. A dual recording configuration of ATP or adenosine sensor placed upon one side of the hypothalamus along with a or inosine sensor that was placed in an equivalent position on the other side of the hypothalamus was used (see main text for details). C, histological identification of the sensor placements in the anterior (left) and posterior (right) hypothalamus. 3V, third cerebral ventricle; AH, anterior hypothalamic area; f, fornix; LH, lateral hypothalamic area; M, mammillary nuclei; MRe, mammillary recess of the third ventricle; OX, optic chiasm; SuM, supramammillary area. Arrows indicate track of the sensor.
Mentions: Rabbits were anaesthetized with a mixture of ketamine hydrochloride (45 mg kg−1, s.c.) and xylazine hydrochloride (10.0 mg kg−1, s.c.) with additional ketamine (20 mg kg−1s.c.) administered every 30 min if necessary. A miniature temperature-sensitive telemetry transmitter (model E-mitter, Minimitter, Sunriver, OR, USA) was implanted into the abdominal cavity of each animal for continuous monitoring of Tb. Then the head of the rabbit was placed in a David Kopf stereotaxic apparatus and two 20-gauge guide cannulae (Plastics One, Roanoke, VA, USA) were implanted either bilaterally into the anterior hypothalamus (stereotaxic co-ordinates: 0.5 mm rostral to bregma, 2.5 mm lateral to midline) or bilaterally into the posterior hypothalamus (2.5 mm caudal to bregma, 2.5 mm lateral to midline) according to the atlas of Sawyer et al. (1954). Each guide cannula was lowered 8 mm from the cortical surface so that the tip was positioned 6 mm dorsal to the desired recording/microinjection sites. Two small screws were placed into the skull, and the cannula was secured in place by dental acrylic. The guide cannula was closed with a dummy cannula that extended from the tip of the guide cannula by ∼1 mm. After surgery, rabbits were housed one per cage, were given penicillin and lidocaine and were allowed to recover for at least 7 days before any experiment. At the end of the experiment the animals were killed humanely by an overdose (200 mg kg−1) of pentobarbitone sodium injected intraperitoneally (i.p.), the brains were removed and the locations of the recording and injection sites were confirmed histologically (Fig. 1C).

Bottom Line: Application of the ATP receptor antagonists pyridoxal-5'-phosphate-6-azophenyl-2',4'-disulphonic acid, Brilliant Blue G or periodate oxidized ATP dialdehyde to the site of ATP release in the anterior hypothalamus markedly augmented and prolonged the febrile response.These data indicate that during the development of the systemic inflammation, ATP is released in the anterior hypothalamus to limit the magnitude and duration of fever.This release may also have a profound effect on the hypothalamic control of other physiological functions in which ATP and related purines have been implicated to play modulatory roles, such as food intake, hormone secretion, cardiovascular activity and sleep.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK. a.gourine@ucl.ac.uk

ABSTRACT
Receptors for extracellular ATP (both ionotropic and metabotropic) are widely expressed in the CNS both in neurones and glia. ATP can modulate neuronal activity in many parts of the brain and contributes to the central nervous control of several physiological functions. Here we show that during the systemic inflammatory response the extracellular concentrations of ATP increase in the anterior hypothalamus and this has a profound effect on the development of the thermoregulatory febrile response. In conscious rabbits we measured ATP release in real time with novel amperometric biosensors and monitored a marked increase in the concentration of ATP (4.0 +/- 0.7 microm) in the anterior hypothalamus in response to intravenous injection of bacterial endotoxin - lipopolysaccharide (LPS). No ATP release was observed in the posterior hypothalamus. The release of ATP coincided with the development of the initial phase of the febrile response, starting 18 +/- 2 min and reaching its peak 45 +/- 2 min after LPS injection. Application of the ATP receptor antagonists pyridoxal-5'-phosphate-6-azophenyl-2',4'-disulphonic acid, Brilliant Blue G or periodate oxidized ATP dialdehyde to the site of ATP release in the anterior hypothalamus markedly augmented and prolonged the febrile response. These data indicate that during the development of the systemic inflammation, ATP is released in the anterior hypothalamus to limit the magnitude and duration of fever. This release may also have a profound effect on the hypothalamic control of other physiological functions in which ATP and related purines have been implicated to play modulatory roles, such as food intake, hormone secretion, cardiovascular activity and sleep.

Show MeSH
Related in: MedlinePlus