Probable involvement of serotonin in the increased permeability of the blood—brain barrier by forced swimming. An experimental study using Evans blue and 131I-sodium tracers in the rat

Sharma, H. S.; Westman, Jan; Navarro, Jorge Cervós; Dey, Prasanta Kumar; Nyberg, Fred

doi:10.1016/0166-4328(96)00170-2

Cited by 103 publications

(74 citation statements)

References 30 publications

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“…Previous reports of changes in BBB permeability with exercise have employed an animal model involving forced swimming (37,40). This exercise model places an animal under severe stress and has been associated with the appearance of hemorrhagic spots on the wall of the stomach and the excretion of fecal pellets (40).…”

Section: Discussionmentioning

confidence: 99%

“…This exercise model places an animal under severe stress and has been associated with the appearance of hemorrhagic spots on the wall of the stomach and the excretion of fecal pellets (40). It is important to note that the breakdown in BBB permeability reported in the series of studies by Sharma and colleagues was particularly severe and widespread, with the extravasation of an albumin-tracer complex (Evans blue and 131 I-labeled sodium) into the brain.…”

Section: Discussionmentioning

confidence: 99%

“…Animal studies have established that the BBB can be widely disrupted after 30 min of forced swimming exercise (37,40). These changes were found to be relatively acute, with normal BBB function restored 2 h after exercise.…”

mentioning

confidence: 99%

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Blood-brain barrier integrity may be threatened by exercise in a warm environment

Watson

Shirreffs

Maughan

2005

American Journal of Physiology-Regulatory, Integrative and Comp

100

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Seven active men were recruited to examine changes in the serum concentration of S100␤, a proposed peripheral marker of blood-brain barrier permeability, following prolonged exercise in temperate (T) and warm (W) conditions. Subjects were seated immersed to the neck in water at 35.0 (0.1)°C (T) or 39.0 (0.1)°C (W) for 30 min. Subjects then entered a room maintained at either 18.3 (1.8)°C (T) or 35.0 (0.3)°C (W) and completed 60 min of cycle exercise at 60% peak oxygen uptake. Serum S100␤ concentration was elevated after exercise in the W trial (ϩ0.12 (0.10) g/l; P ϭ 0.02) but not after the T trial (P ϭ 0.238). Water immersion and exercise elevated core temperature by 2.1 (0.5)°C to 39.5 (0.3)°C at the end of exercise in the W trial compared with a 0.9 (0.2)°C increase during the T trial (P Ͻ 0.001). Weighted mean skin temperature was higher throughout the W trial compared with the T trial (P Ͻ 0.001). Heart rate (P Ͻ 0.001) and blood glucose (P Ͻ 0.001) and lactate (P Ͻ 0.001) concentrations were elevated to a greater extent during exercise in the W trial than in the T trial. Ratings of perceived exertion (P Ͻ 0.001) and thermal comfort (P Ͻ 0.001) were markedly higher throughout the W trial than in the T trial. The results of this study demonstrate that serum S100␤ was elevated after water immersion and prolonged exercise in a warm environment, suggesting that blood-brain barrier permeability may be altered. central fatigue; central nervous system; hyperthermia THE CAPACITY TO PERFORM PROLONGED exercise is significantly reduced when exercise is performed in a warm environment (12). In contrast to temperate conditions, fatigue during endurance exercise in high ambient temperatures does not appear to be adequately explained by the depletion of muscle glycogen or by cardiovascular and fluid balance factors (25). Recent studies have provided evidence that hyperthermia profoundly influences brain function during exercise, resulting in altered brain activity (24), reduced voluntary activation of muscle during sustained contractions (26), and increased perception of effort (27). Fatigue may be mediated through mechanisms residing within the central nervous system (CNS), but at present the neurobiological mechanisms that may be involved are not apparent.The blood-brain barrier (BBB) is a dynamic structure consisting of microvascular endothelial cells, characterized by the presence of tight junctions and restricted vesicular transport. The foot processes of surrounding astrocytes and the presence of pericytes reinforce these tight junctions. The BBB functions through these specialized structures to maintain a stable environment for the CNS by tightly regulating the exchange of molecules between the CNS and the peripheral circulation. When the BBB is intact, diffusion is largely restricted, with transport mediated through a series of selective molecular carrier systems specific to a wide range of substances, including glucose, amino acids, vitamins, electrolytes, and peptides (13).The BBB is largely resistant to changes ...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Blood-brain barrier integrity may be threatened by exercise in a warm environment

Watson

Shirreffs

Maughan

2005

American Journal of Physiology-Regulatory, Integrative and Comp

100

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“…f/f/p mice in inflammatory pain Serotonin does not cross the blood-brain barrier (BBB) under normal circumstances, but the permeability of the BBB has been shown to increase after acute stress (Sharma et al, 1995;Esposito et al, 2001), possibly because of the activation of mast cells and the release of corticotrophin-releasing hormone (Esposito et al, 2002). To determine whether formalin-or carrageenan-evoked pain behaviors of the mutant mice may be impacted by peripheral 5-HT because of increased BBB permeability in response to stress in inflammatory states, the concentrations of 5-HT and its metabolite 5-HIAA in the CNS of Lmx1b f/f/p mice were measured after intraplantar injections of formalin, carrageenan, or vehicle.…”

Section: -Ht and 5-hiaa Are Not Altered In The Cns Of Lmx1bmentioning

confidence: 99%

Mice Lacking Central Serotonergic Neurons Show Enhanced Inflammatory Pain and an Impaired Analgesic Response to Antidepressant Drugs

Zhao¹,

Chiechio²,

Sun³

et al. 2007

J. Neurosci.

125

101

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“…For instance 5HT 2 R agonists readily penetrate the blood-brain barrier while 5HT 2 R antagonists like ketanserin do not (Michiels et al, 1988). Indeed, ketanserin acts on 5HT 2 receptors to block the passage of 5-HT through the blood-brain barrier (Sharma et al, 1995). Thus ketanserin could block 5-HT action on the EOD by preventing its passage into the brain.…”

mentioning

confidence: 99%

Opposing actions of 5HT1A and 5HT2-like serotonin receptors on modulations of the electric signal waveform in the electric fish Brachyhypopomus pinnicaudatus

Allee

Markham

Salazar

et al. 2008

Hormones and Behavior

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Serotonin (5-HT) is an indirect modulator of the electric organ discharge (EOD) in the weakly electric gymnotiform fish, Brachyhypopomus pinnicaudatus. Injections of 5-HT enhance EOD waveform "masculinity", increasing both waveform amplitude and the duration of the second phase. This study investigated the pharmacological identity of 5-HT receptors that regulate the electric waveform and their effects on EOD amplitude and duration. We present evidence that two sets of serotonin receptors modulate the EOD in opposite directions. We found that the 5HT 1A R agonist 8-OH-DPAT diminishes EOD duration and amplitude while the 5HT 1A R antagonist WAY100635 increases these parameters. In contrast, the 5HT 2 R agonist α-Me-5-HT increases EOD amplitude but not duration, yet 5-HT-induced increases in EOD duration can be inhibited by blocking 5HT 2A/2C -like receptors with ketanserin. These results show that 5-HT exerts bi-directional control of EOD modulations in B. pinnicaudatus via action at receptors similar to mammalian 5HT 1A and 5HT 2 receptors. The discordant amplitude and duration response suggests separate mechanisms for modulating these waveform parameters. KeywordsSerotonin; Electric organ discharge; Communication signal; 5HT 1A receptor; 5HT 2 receptor; Social interaction; Dominance hierarchy Serotonin (5-HT) is a neuromodulator so ubiquitous that hardly any physiological function or behavior is free from its direct or indirect effects. As a result, a full account of neuroendocrine control of behavior requires a thorough assessment of 5-HT's function across a wide range of circumstances, even as the pervasive presence of 5-HT in the nervous system complicates unambiguous assessment of its functions. Particularly, serotonin is involved in the regulation of diametrically opposed behaviors, aggression and subordinance (Summers and Winberg, 2006). Serotonin activity rises in both dominant and subordinate males but rapidly returns to baseline in dominants while it stays chronically high in subordinates (Overli et al., 1999;Summers and Winberg, 2006). Prior social defeat or success during aggressive interactions affects future aggressive behaviors and the activity of the serotonergic system (Winberg et al., 1992;Winberg et al., 1997b). Furthermore, social experience affects the regulatory effect of serotonin on dominant behaviors via serotonin receptors 1A and 2A (Yeh et al., 1996). Pharmaceutical 5HT 1A agonists inhibit aggression or induce submissive behaviors in a wide range of non-mammalian vertebrates including green anoles (Deckel and Fuqua, 1998), Arctic charr (Hoglund et al., 2002;Winberg and Nilsson, 1993) Bell et al., 2007). In addition, 5HT 1A receptors operate as both postsynaptic receptors and as pre-synaptic autoreceptors to either suppress or stimulate stress responses in teleosts as they do in mammals (Hoglund et al., 2002). Despite the functionally and anatomically conserved nature of the serotonin system in vertebrates (Parent et al., 1984) and the abundance of data indicating a role for 5HT ...

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Probable involvement of serotonin in the increased permeability of the blood—brain barrier by forced swimming. An experimental study using Evans blue and 131I-sodium tracers in the rat

Cited by 103 publications

References 30 publications

Blood-brain barrier integrity may be threatened by exercise in a warm environment

Blood-brain barrier integrity may be threatened by exercise in a warm environment

Mice Lacking Central Serotonergic Neurons Show Enhanced Inflammatory Pain and an Impaired Analgesic Response to Antidepressant Drugs

Opposing actions of 5HT1A and 5HT2-like serotonin receptors on modulations of the electric signal waveform in the electric fish Brachyhypopomus pinnicaudatus

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