Clonidine but not propranolol decreases plasma neuropeptide Y (NPY) levels

Mf, Poncet; Damase‐Michel, Christine; Valet, Philippe; Ma, Tran; Jl, Montastruc; Montastruc, P

doi:10.1111/j.1472-8206.1991.tb00733.x

Cited by 7 publications

(2 citation statements)

References 20 publications

(15 reference statements)

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“…The response was linear for concentrations ranging from 25 to 3000 pmol 1-1. The detection limit was 25 pmol 1as previously reported (Poncet et al, 1991). Day to day variability was 4% and within-run 3%.…”

Section: Measurement Of Plasma Hormone Levelssupporting

confidence: 58%

Central cardiovascular effects of acetylcholine in the conscious dog

Brefel¹,

Lazartigues²,

Tran³

et al. 1995

British J Pharmacology

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Section: Measurement Of Plasma Hormone Levelssupporting

confidence: 58%

Central cardiovascular effects of acetylcholine in the conscious dog

Brefel¹,

Lazartigues²,

Tran³

et al. 1995

British J Pharmacology

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“…The electrochemical detector response was linear for concentrations ranging from 60 pmol 11 to 600 nmol I-'. In these conditions, the detection limit is 60 pmol 1-1 to 600 nmol I'- (Poncet et al, 1991;Tavernier et al, 1993).…”

Section: Blood Sampling and Catecholamine Assaysmentioning

confidence: 99%

A study of tolerance to apomorphine

Montastruc

Llau

Senard

et al. 1996

British J Pharmacology

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1 The present study was designed to investigate tolerance to several pharmacological effects of apomorphine. 2 Changes in blood pressure, heart rate, plasma noradrenaline levels, rectal temperature, respiratory rate and retching plus vomiting were compared after administration of apomorphine (200 jig kg-', i.v. as a bolus) or saline at different time intervals (30, 120 and 720 min) in four groups of chloraloseanaesthetized dogs. 3 The first administration of apomorphine induced a significant decrease in blood pressure and rectal temperature, a marked rise in heart rate with no change in noradrenaline plasma levels or respiratory rate. Emesis occurred in 71% of the animals. 4 A second administration of apomorphine 30 min later failed to modify blood pressure or heart rate. In contrast, the magnitude of apomorphine-induced changes in blood pressure and heart rate was similar to that observed after the first administration when apomorphine was given 120 or 720 min later. 5 The apomorphine-induced decrease in rectal temperature evoked by a second dose of apomorphine was less marked when given 30 and 120 min after the first dose and unchanged when given 720 min later. 6 The number of animals exhibiting retching and vomiting was lower when apomorphine was reinjected after 30 min than when the time between two successive injections of apomorphine was 120 or 720 min. 7 These results show that tolerance to apomorphine involves its cardiovascular, hypothermic and emetic effects. The time course of tolerance to repeated injections of apomorphine is longer for its hypothermic than for its hypotensive or emetic effects. This suggests a tissue-specific regulation of D2 dopamine receptors to repeated injections of apomorphine.

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Effects of clonidine, dihydralazine and splanchnic nerve stimulation on the release of neuropeptide Y, MET-enkephalin and catecholamines from dog adrenal medulla

Damase‐Michel

Tavernier

Giraud

et al. 1993

Naunyn-Schmiedeberg's Arch Pharmacol

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Various neuropeptides are costored together with catecholamines in the adrenal medulla. The concurrent release (evaluated by adrenal vein plasma levels) of these neuropeptides [neuropeptide Y (NPY), met-enkephaline (ME)] and catecholamines [adrenaline (A) and noradrenaline (NA)] from the adrenal gland was examined in chloralose-anesthetized dogs after intravenous administration of clonidine (10 micrograms/kg) and dihydralazine (1 mg/kg). These results were compared to those obtained after the stimulation of the right splanchnic nerve at 1, 5 and 10 Hz frequencies. The increment in the release of catecholamines and neuropeptides was evaluated for dihydralazine and splanchnic nerve stimulation. Dihydralazine (at its maximal effect) induced a significant preferential increase in catecholamines (expressed as mean (SEM): NA: 17.3 (5.4) fold, A: 13.1 (2.6) fold) and ME (16.0 (7.1) fold) versus basal values. However, the significant increase in NPY-LI was only 2.0 (0.4) times the baseline. Splanchnic nerve stimulation induced a frequency-dependent increase in catecholamines and neuropeptides. When the stimulation frequency was increased from 1 Hz to 5 Hz, NA and A levels increased 17.9 (4.3) and 14.0 (2.2) fold, respectively and ME levels 14.1 (3.0) fold. By contrast, NPY-LI was increased only 2.3 (0.3) fold under the same conditions. Increasing the stimulation frequency from 5 Hz to 10 Hz resulted in similar elevations of NA, ME, and NPY-LI adrenal plasma levels (about 4 times) whereas A only increased twice. Clonidine decreased catecholamine and ME adrenal plasma levels (the maximal percent decrease when compared with control values was about 75%) whereas NPY adrenal plasma levels remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

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Clonidine but not propranolol decreases plasma neuropeptide Y (NPY) levels

Cited by 7 publications

References 20 publications

Central cardiovascular effects of acetylcholine in the conscious dog

Central cardiovascular effects of acetylcholine in the conscious dog

A study of tolerance to apomorphine

Effects of clonidine, dihydralazine and splanchnic nerve stimulation on the release of neuropeptide Y, MET-enkephalin and catecholamines from dog adrenal medulla

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