| 1. |
- Olsson, Marie, 1971, et al.
(författare)
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Paroxetine influences respiration in rats: implications for the treatment of panic disorder.
- 2004
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Ingår i: European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology. - 0924-977X .- 1873-7862. ; 14:1, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Since hyperventilation and shortness of breath are characteristic features of panic attacks, and since the attacks can be elicited by CO(2) inhalation, an involvement of central or peripheral chemoreceptors in the pathophysiology of panic disorder has been suggested. Prompted by clinical reports suggesting that the susceptibility to spontaneous as well as CO(2)-induced anxiety and hyperventilation is attenuated by serotonin reuptake inhibitors (SRIs), we undertook the present study in order to explore the possible effect of an SRI, paroxetine, on baseline respiration and CO(2)-induced hyperventilation in freely moving Wistar rats. A significant increase in baseline respiratory rate was seen both after 5 and 15 weeks of treatment with paroxetine. CO(2) exposure induced a dose-dependent increase in respiratory rate, but not tidal volume, in both paroxetine-treated rats and controls; this response was reduced after 15 weeks of paroxetine treatment, but not after 5 weeks of treatment. We suggest that an influence on the regulation of respiration may be of importance for the anti-panic effect of SRIs.
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| 2. |
- Annerbrink, Kristina, 1974, et al.
(författare)
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Acute and chronic treatment with serotonin reuptake inhibitors exert opposite effects on respiration in rats: possible implications for panic disorder.
- 2009
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Ingår i: Journal of psychopharmacology (Oxford, England). - : SAGE Publications. - 1461-7285 .- 0269-8811. ; 24:12, s. 1793-1801
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Tidskriftsartikel (refereegranskat)abstract
- Prompted by the suggested importance of respiration for the pathophysiology of panic disorder, we studied the influence of serotonin reuptake inhibitors (SRIs) as well as other serotonin-modulating compounds on respiration in freely moving rats. The effect on respiration after acute administration of compounds enhancing synaptic levels of serotonin, that is, the serotonin reuptake inhibitors paroxetine and fluoxetine, the serotonin-releasing agents m-chlorophenylpiperazine and d-fenfluramine, and the selective 5-HT1A antagonist WAY-100635, were investigated. All serotonin-releasing substances decreased respiratory rate in unrestrained, awake animals, suggesting the influence of serotonin on respiratory rate under these conditions to be mainly inhibitory. In line with a previous study, rats administered fluoxetine for 23 days or more, on the other hand, displayed an enhanced respiratory rate. The results reinforce the assumption that the effect of subchronic administration of a serotonin reuptake inhibitor on certain serotonin-regulated parameters may be opposite to that obtained after acute administration. We suggest that our observations may be of relevance for the fact that acute administration of SRIs, d-fenfluramine, or m-chlorophenylpiperazine often is anxiogenic in panic disorder patients, and that weeks of administration of an SRI leads to a very effective prevention of panic.
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| 3. |
- Annerbrink, Kristina, 1974, et al.
(författare)
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Serotonin depletion increases respiratory variability in freely moving rats: implications for panic disorder.
- 2003
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Ingår i: The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). - 1469-5111. ; 6:1, s. 51-6
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate if serotonergic transmission affects respiratory variability, a parameter consistently found increased in patients with panic disorder, we studied the effect of a serotonin synthesis inhibitor, para-chlorophenylalanine (PCPA), on respiratory variability at baseline and during CO2-induced hyperventilation in awake and unrestrained rats. Forty male Wistar rats were given intraperitoneal injections of PCPA (300 mg/kg) or saline 72, 48 and 24 h before registration of respiration in a plethysmograph allowing the animals to move freely. PCPA-treated rats displayed significantly higher tidal volume variability and minute volume variability, both at baseline and during CO2 exposure, compared to controls. The results support the notion that serotonin dysfunction may contribute to the enhanced respiratory variability observed in patients with panic disorder.
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| 4. |
- Melchior, Lydia K, 1979, et al.
(författare)
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Association between estrus cycle-related aggression and tidal volume variability in female Wistar rats.
- 2004
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Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530. ; 29:8, s. 1097-100
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Tidskriftsartikel (refereegranskat)abstract
- Premenstrual dysphoria is characterized by symptoms such as irritability and depressed mood, present during the luteal phase of the menstrual cycle, and disappearing shortly after the onset of menstruation. Subjects with premenstrual dysphoria have previously been reported to display enhanced respiratory variability, and to experience anxiety when exposed to panicogens, such as CO2. In the present study, the possible influence of the estrus cycle and estrus cycle-related aggression on respiratory variability was investigated in female rats of the Wistar strain. The rats were subdivided into two groups: those displaying estrus cycle-related aggression, as evaluated using the resident intruder paradigm, and those not showing aggression throughout the estrus cycle. This model has been developed to serve as an animal model of premenstrual irritability. The former group was found to display higher tidal volume variability in diestrus, as compared to the non-aggressive rats. There was no effect of estrus cycle phase on respiratory variability. These results are well in line with the clinical observation that women with premenstrual dysphoria display higher respiratory variability than controls, and the notion that respiratory variability is a parameter of interest in this context. In our opinion, they also strengthen the concept of this animal model as a model of premenstrual irritability.
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| 5. |
- Olsson, Marie, 1971, et al.
(författare)
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Association between estrus cycle-related changes in respiration and estrus cycle-related aggression in outbred female Wistar rats.
- 2003
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Ingår i: Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 0893-133X. ; 28:4, s. 704-10
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Tidskriftsartikel (refereegranskat)abstract
- Premenstrual dysphoric disorder is characterized by irritability surfacing during the luteal phase of the menstrual cycle, and disappearing shortly after the onset of menstruation. Although the cardinal symptoms of premenstrual dysphoria are different from those of panic disorder, the two conditions share a number of traits indicating that they both may be associated with abnormalities in the regulation of respiration. Both subjects with panic disorder and subjects with premenstrual dysphoria are hence reported to display enhanced respiratory variability, and to experience anxiety when exposed to CO(2). In the present study, the possible influence of the estrus cycle on respiratory parameters in outbred female rats of the Wistar strain was investigated. Before being tested with respect to respiration, the rats were subdivided into two groups: those displaying estrus cycle-related variation in aggression, as evaluated using the resident intruder paradigm, and those not showing aggression throughout the cycle. Whereas the former group was found to display higher respiratory rate during the diestrus phase than during the proestrus/estrus phase, no cycle-related variation in respiration was observed in animals not showing cycle-related variation in aggression. The results support previous studies indicating that the estrus cycle exerts an influence on respiration, and suggest that rats prone to cycle-related aggression are more sensitive also to the influence of hormonal cyclicity on respiration. The possible bearing of these findings for the aberration in respiration displayed by subjects with premenstrual dysphoria is discussed.
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| 6. |
- Olsson, Marie, 1971, et al.
(författare)
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Intracerebroventricular administration of the angiotensin II receptor antagonist saralasin reduces respiratory rate and tidal volume variability in freely moving Wistar rats.
- 2004
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Ingår i: Psychoneuroendocrinology. - 0306-4530. ; 29:1, s. 107-12
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Tidskriftsartikel (refereegranskat)abstract
- The possible importance of intra-individual variations in respiratory rate and tidal volume has recently gained interest in psychiatric research, as a result of the observations that patients with panic disorder or premenstrual dysphoric disorder display enhanced respiratory variability as compared to controls. Although the role of brain neurotransmitters in the regulation of breathing has been extensively studied, as yet data on the central regulation of respiratory variability is sparse. Prompted by previous studies indicating that angiotensin II (ANG II) may influence ventilation as well as anxiety, we have studied the effect of intracerebroventricular administration of an ANG II receptor antagonist, saralasin, on respiratory variability in unrestrained, freely moving male Wistar rats. Treatment with saralasin, 5 mug dissolved in 1 mul saline followed by 9 mul saline in each lateral cerebral ventricle, did not influence tidal volume, but markedly reduced tidal volume variability (p=0.0005), as compared to saline injections (10 mul). Respiratory rate was reduced by saralasin (p=0.02), and there was also a non-significant tendency for a reduction in respiratory rate variability. Both minute volume (p=0.005) and volume/10 s variability (p=0.0006) were reduced. It is suggested that ANG II in the brain of Wistar rats may regulate respiratory rate and tidal volume variability.
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