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- Naylor, Andrew Stuart, 1977, et al.
(författare)
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Extended voluntary running inhibits exercise-induced adult hippocampal progenitor proliferation in the spontaneously hypertensive rat.
- 2005
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Ingår i: Journal of neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 93:5, s. 2406-14
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Tidskriftsartikel (refereegranskat)abstract
- Previous work has shown that voluntary running increases cell proliferation and neurogenesis in the dentate gyrus of the adult hippocampus. Here we report that long-term running for 24 days results in a down-regulation of hippocampal progenitor proliferation to one-half the level of nonrunning controls compared with a fivefold increase in progenitor proliferation seen after 9 days of voluntary running (short-term running). The negative effects seen on proliferation after 24 days of running were prevented by restricting daily running distances (by 30-50%) during 24 days. Long-term running for 24 days increases the response of the hypothalamic-pituitary-adrenal axis, with an increase in adrenal gland weight and increased plasma corticosterone levels, as well as decreased thymus weight, indicating a stress response as a possible mediator of decreased progenitor proliferation. Furthermore, the negative effects seen on the observed stress response after 24 days of running were prevented by restricting daily running distance. Short-term running did not alter these stress parameters compared with nonrunning controls. However, it increased phosphorylated cyclic AMP response element binding protein (pCREB) in the dentate gyrus, an increase that was not seen in nonrunning controls or after 24 days of running. Taken together, these data suggest that voluntary running does not always enhance proliferation and that the decrease in progenitor proliferation seen in long-term running is possibly mediated by mechanisms involving a stress response in the animal. However, a moderate level of long-term running was able to prevent the negative stress-related changes seen in unrestricted long-term running.
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| 2. |
- Persson, Anders I., 1973, et al.
(författare)
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Comparison of immunoblotted delta opioid receptor proteins expressed in the adult rat brain and their regulation by growth hormone.
- 2005
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Ingår i: Neuroscience research. - : Elsevier BV. - 0168-0102. ; 52:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- It has previously been suggested that exogenous growth hormone (GH) affect quality of life and higher brain functions through the endogenous opioid system. Recently, we showed that GH down-regulate 72 and 48 kDa delta opioid receptor (DOR) proteins in the adult rat cerebral cortex and cerebellum. In the present study, we found that an antiserum raised against the N-terminus of the DOR also recognizes a 36 kDa protein, not recognized by a C-terminus-directed antiserum. We aimed to investigate the identity of the 72, 48 and 36 kDa proteins and to further study the effects of GH on their expression in different brain regions. The expression was studied in hypophysectomized (Hx) and untreated normal female rats. One subgroup of Hx rats received GH as a daily subcutaneous injection for 19 days. Our data show that treatment with GH in Hx rats normalized the expression of the 72 kDa protein in the cerebral cortex, whereas no significant effect were observed for the 48 or 36 kDa proteins. However, GH significantly reduced the ratio between the 72 and 36 kDa proteins in different brain regions of Hx rats. Our data suggest that GH reduces the levels of a 72 kDa DOR that likely represents a dimeric form of a 36 kDa DOR post-translationally truncated at the C-terminus, and that altered receptor dimerization may be involved in GH induced effects in the central nervous system.
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