Changes in monamines and their metabolite levels in some brain regions of aged rats

Ponzio, F.; Calderini, G.; Lomuscio, G; Vantini, G.; Toffano, G.; Algeri, S.

doi:10.1016/0197-4580(82)90057-4

Cited by 154 publications

(58 citation statements)

References 19 publications

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“…The number of serotonergic neurons, 5-HT and 5HIAA concentrations, 5-HT receptor density, and 5-HT reuptake protein change with age in different central nervous system (CNS) regions (10,27,32,37,48,52,57,67). Some of these changes exhibit sexual dimorphism (7) because the serotonergic system is influenced by sex hormones.…”

mentioning

confidence: 99%

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

Zabka¹,

Mitchell²,

Olson³

et al. 2003

Journal of Applied Physiology

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Zabka, A. G., G. S. Mitchell, E. B. Olson, Jr., and M. Behan. Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats. J Appl Physiol 95: 2614-2623. First published August 22, 2003 10.1152/japplphysiol.00476.2003.-Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats (72). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF (41); thus we further predicted that CIH would restore LTF in geriatric female rats. LTF was measured in young (3-4 mo) and geriatric (20-22 mo) female Sasco Sprague-Dawley rats and in a group of geriatric rats exposed to 1 wk of nocturnal CIH (11 vs. 21% O 2 at 5-min intervals, 12 h/night). In anesthetized, paralyzed, vagotomized, and ventilated rats, time-dependent hypoxic phrenic and XII responses were assessed. The short-term hypoxic response was measured during the first of three 5-min episodes of isocapnic hypoxia (arterial PO 2 35-45 Torr). LTF was assessed 15, 30, and 60 min postepisodic hypoxia. Phrenic and XII short-term hypoxic response was not different among groups, regardless of CIH treatment (P Ͼ 0.05). LTF in geriatric female rats was smaller than previously reported for middle-aged rats but comparable to that in young female rats. CIH augmented phrenic and XII LTF to levels similar to those of middle-aged female rats without CIH (P Ͻ 0.05). The magnitude of phrenic and XII LTF in all groups was inversely related to the ratio of progesterone to estradiol serum levels (P Ͻ 0.05). Thus CIH and sex hormones influence the magnitude of LTF in geriatric female rats. respiratory control; plasticity; age; sex hormones AGE AFFECTS THE CONTROL OF breathing in humans and other mammals (6,12,61,63), and there are striking differences between males and females with advancing age. For example, responses to hypoxia are decreased in middle-aged male rats but increased in middle-aged female rats (19,62,71,72). A form of serotonin (5-HT)-dependent respiratory plasticity, long-term facilitation (LTF), increases in middleaged female rats but decreases dramatically in middle-aged male rats (71, 72). The control of breathing is also influenced by sex hormones (7, 60, 66). However, relatively little is known concerning specific mechanisms of respiratory control affected by age and/or sex hormones.In the present study, we investigated the effects of old age on selected time-dependent respiratory responses during and after episodic hypoxia in female rats, with a focus on the short-term hypoxic response (STHR) and LTF. STHR and LTF have been studied extensively in young and middle-aged, but not in geriatric, male and female rats (20,50,58,71,72).Respiratory LTF is a form of plasticity elicited by episodic hypoxia or e...

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mentioning

confidence: 99%

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

Zabka¹,

Mitchell²,

Olson³

et al. 2003

Journal of Applied Physiology

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“…The present findings regarding the abovementioned shifts are based primarily on an increase in 5-HT levels. However, previous studies have reported increases [37][38], no change [39][40], or even decreases [41][42] in 5-HT levels elicited by age. Thus, the influence of age on brain 5-HT levels remains controversial.…”

Section: Effects Of Age On Brain Trp Metabolismmentioning

confidence: 92%

Shifts in the balance of brain tryptophan metabolism due to age and systemic administration of lipopolysaccharide

Matsui¹,

Shirokawa²,

Ozaki³

et al. 2010

Health

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The kynurenine (KYN) pathway, which is initiated by indoleamine 2, 3-dioxygenase (IDO), is a key tryptophan (TRP) metabolic pathway. It shares TRP with the serotonin (5-HT) pathway. Because activation of the KYN pathway by proinflammatory cytokines induces depressive symptoms, shifts in the balance of TRP metabolism to the KYN pathway are closely related to the etiology of depression. In the present study, the influence of age on the effect of the inflammation response system (IRS) on brain TRP metabolism was investigated. Male ICR mice (PND21) were reared for 4 weeks (younger group) or until they reached 1 year of age (older group), and given an intraperitoneal (i.p.) injection of lipopolysaccharide (LPS). The TRP, KYN, and 5-HT levels were measured in the prefrontal cortex, hippocampus, amygdala, and dorsal raphe nuclei. An increase in TRP and 5-HT levels was observed with age in all brain regions, whereas age was associated with decreases in KYN levels in the dorsal raphe nuclei. In all brain regions, LPS increased TRP levels, while it increased KYN levels in the prefrontal cortex and amygdala. Reduced KYN/5-HT ratios in all regions were observed with age, whereas increased KYN/5-HT ratios were observed with LPS in all regions except the dorsal raphe nuclei. Thus, age shifted the balance between the KYN and 5-HT pathways toward the 5-HT pathway, and countered the effects of LPS, which shifted the balance to the KYN pathway. These effects are relevant to the etiology of psychiatric disorders in elderly people.

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“…In animal model studies of aging effects on DA regulation, no study has shown loss of DA or TH to reach that of the symptomatic threshold of striatal DA or TH loss. In fact, while some studies do show loss of DA or TH approaching that seen in PD, ~60% (Collier et al, 2007)), many studies report much less, if any, loss of striatal DA or TH (Ponzio et al, 1982;Marshall and Rosenstein, 1990;Emerich et al, 1993;Irwin et al, 1994;Hebert and Gerhardt, 1998;Yurek et al, 1998;Gerhardt et al, 2002;Haycock et al, 2003;Cruz-Muros et al, 2007;Salvatore et al, 2009). In fact, 60% striatal DA loss still does not produce bradykinesia in a PD model (Bezard et al, 2001).…”

Section: Tyrosine Hydroxylase Regulation In Aging-related Parkinsonismmentioning

confidence: 99%

Targeting Tyrosine Hydroxylase to Improve Bradykinesia

Salvatore¹

2012

Mechanisms in Parkinson's Disease - Models and Treatments

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Changes in monamines and their metabolite levels in some brain regions of aged rats

Cited by 154 publications

References 19 publications

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

Shifts in the balance of brain tryptophan metabolism due to age and systemic administration of lipopolysaccharide

Targeting Tyrosine Hydroxylase to Improve Bradykinesia

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