| 51. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Muscle contractions induce interleukin-6 mRNA production in rat skeletal muscles.
- 2000
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Ingår i: The Journal of physiology. - 0022-3751. ; 528 Pt 1, s. 157-63
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Tidskriftsartikel (refereegranskat)abstract
- 1. The present study explored the hypothesis that interleukin-6 (IL-6) might be locally produced in response to skeletal muscle contractions and whether the production might reflect the type of muscle contraction performed. Rats were anaesthetized and the calf muscles of one limb were stimulated electrically for concentric or eccentric contractions (4 x 10 contractions with 1 min of rest between the 4 series, 100 Hz). The contralateral muscles served as unstimulated controls. The mRNA levels for IL-6, the glucose transport protein GLUT-4 and beta-actin in the rat muscles (white and red gastrocnemius and soleus) were quantified by quantitative competitive RT-PCR. 2. The IL-6 mRNA level, measured 30 min after the stimulation, increased after both eccentric and concentric contractions and there were no significant differences in IL-6 mRNA levels between the different muscle fibre types. No significant increase in IL-6 mRNA level was seen in the unstimulated contralateral muscle fibres. 3. No increase in GLUT-4 mRNA level was detected, indicating that the increase in IL-6 mRNA level was not due to general changes in transcription. 4. We conclude that IL-6 is locally produced after muscle contraction, with no significant differences between different muscle fibre types. This local production of IL-6 is not due to general changes in transcription, since no changes in the level of GLUT-4 mRNA were found. The fact that increased IL-6 mRNA levels were seen after both concentric and eccentric contractions indicates that the production of IL-6 is not solely due to muscle damage, seen primarily after eccentric exercise.
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| 52. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Natural immunity and chronic exercise in rats. The involvement of the spleen and the splenic nerves.
- 1996
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Ingår i: Life sciences. - 0024-3205. ; 58:23, s. 2137-46
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that voluntary running for 4-5 weeks in the spontaneously hypertensive rat (SHR) significantly increased in natural cytotoxic mechanism in vivo, measured as clearance of 51Cr YAC-1 lymphoma cells from the lungs. In the present study, we have studied the possible role of the spleen and the splenic nerves in this augmentation. The SHR were randomly allocated to either a voluntary exercise group or a sedentary control group. After four weeks of exercise the runners and sedentary control SHR were further assigned to one of four groups: 1) no surgery, 2) sham operation, 3) splenic nerve section and 4) splenectomy. Splenectomy drastically reduced in vivo cytotoxicity in both runners and sedentary controls, but in vivo cytotoxicity of splenectomized voluntary runners was significantly higher than that of splenectomized sedentary control animals. Selective denervation of the spleen did not affect the in vivo cytotoxicity. These results indicate that the enhanced in vivo natural cytotoxic mechanism following voluntary chronic exercise in SHR is partly dependent on intact splenic function. However, this enhancement does not seem to be mediated by the splenic sympathetic nerves.
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| 53. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Physical exercise, endogenous opioids and immune function.
- 1997
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Ingår i: Acta physiologica Scandinavica. Supplementum. - 0302-2994. ; 640, s. 47-50
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Forskningsöversikt (refereegranskat)abstract
- The experimental data available today strongly indicate that various types of physiological stressors, including physical exercise and emotional stress, can influence immune function. Natural immunity represents a first line of defence in viral infections and cytotoxicity to a variety of tumour cells. Natural immunity is strongly influenced by chronic exercise and this regulation includes interaction between the nervous, endocrine and immune systems. Central mechanisms including the endogenous opioids are of great interest. Chronic activation of endogenous opioid systems augments natural cytotoxicity and the possible involvement the opioids in the exercise-induced enhancement of natural immunity is discussed. Also, catecholamines seem to play an important role in the regulation of immune function, both after chronic exercise and emotional stress. The physiological significance of the reported changes in natural cytotoxicity after exercise-training is as yet unclear.
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| 54. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Somatic nerve stimulation and cholera-induced net fluid secretion in the small intestine of the rat: evidence for an opioid effect.
- 1999
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Ingår i: Journal of the autonomic nervous system. - 0165-1838. ; 78:1, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- The effects of somatic nerve stimulation on cholera toxin induced secretion was investigated in vivo in anaesthetised rats. Small intestinal secretion was induced with cholera toxin and measured by a gravimetric technique. Afferent stimulation (pulse frequency within train; 100 Hz; train duration: 50 ms; train frequency: 3 Hz) of the sciatic nerve over 30 min significantly reduced the net fluid secretion both during (P < 0.05) and after cessation of the stimulation (P < 0.01). The greatest effect was obtained immediately after the termination of the nerve stimulation when the secretion was reversed to net fluid absorption. The opioid receptor antagonist naloxone (10 mg kg(-1) i.v.) administrated during the stimulation, significantly inhibited the antisecretory effect seen after the stimulation, thus no significant difference was seen between the control period and the periods after cessation of the stimulation. The opioid receptor antagonist naloxone methiodide (10 mg kg(-1) i.v.), which does not cross the blood-brain barrier, partly inhibited the antisecretory effects but not with the same magnitude as naloxone, thus the net fluid secretion was still significantly inhibited after the stimulation (P < 0.05). We conclude that afferent stimulation of the sciatic nerve strongly inhibits the cholera toxin induced secretion in the small intestine. This inhibition involves primarily a central opioid mechanism and to a lesser extent peripheral opioid mechanism.
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| 55. |
- Jonsdottir, Ingibjörg H, 1966
(författare)
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Special feature for the Olympics: effects of exercise on the immune system: neuropeptides and their interaction with exercise and immune function.
- 2000
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Ingår i: Immunology and cell biology. - 0818-9641. ; 78:5, s. 562-70
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Forskningsöversikt (refereegranskat)abstract
- It is known today that the immune system is influenced by various types of psychological and physiological stressors, including physical activity. It is well known that physical activity can influence neuropeptide levels both in the central nervous system as well as in peripheral blood. The reported changes of immune function in response to exercise have been suggested to be partly regulated by the activation of different neuropeptides and the identification of receptors for neuropeptides and steroid hormones on cells of the immune system has created a new dimension in this endocrine-immune interaction. It has also been shown that immune cells are capable of producing neuropeptides, creating a bidirectional link between the nervous and immune systems. The most common neuropeptides mentioned in this context are the endogenous opioids. The activation of endogenous opioid peptides in response to physical exercise is well known in the literature, as well as the immunomodulation mediated by opioid peptides. The role of endogenous opioids in the exercise-induced modulation of immune function is less clear. The present paper will also discuss the role of other neuroendocrine factors, such as substance P, neuropeptide Y and vasoactive intestinal peptide, and pituitary hormones, including growth hormone, prolactin and adrenocorticotrophin, in exercise and their possible effects on immune function.
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| 56. |
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| 57. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Stress och fysisk aktivitet
- 2013. - 3
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Ingår i: Stress. - Stockholm : Liber. - 9789147105410 ; , s. 175-180
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 58. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Stress och fysisk aktivitet
- 2005
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Ingår i: Stress; Individen, samhället, organisationen, molekylerna. Ed; Ekman, R, Arnetz, B. - Stockholm : Liber förlag. - 9789147052585 ; , s. 240-43
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 59. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Stress och minnesfunktion
- 2007
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Ingår i: Socialmedicinsk tidskrift. ; årg 84:2
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Forskningsöversikt (refereegranskat)
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| 60. |
- Jonsdottir, Ingibjörg H, 1966
(författare)
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Stress och påverkan på immunförsvaret
- 2005
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Ingår i: Stress; Individen, samhället, organisationen, molekylerna. Ed; Ekman, R, Arnetz, B. - Stockholm : Liber förlag.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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