Search results for "substitut"
showing 10 items of 1337 documents
Interplay between PACAP and NO in mouse ileum
2003
Abstract We investigated the possibility that pituitary adenylate cyclase activating peptide (PACAP) has a role in the control of contractility in the mouse ileum. PACAP-(1-27) produced tetrodotoxin (TTX)-insensitive, concentration-dependent reduction of the amplitude of the spontaneous contractions of longitudinal muscle up to their complete disappearance. This effect was inhibited by PACAP-(6-38), PACAP receptor antagonist, and by apamin, blocker of small-conductance Ca2+-activated K+-channels. Nω-nitro- l -arginine methyl ester (L-NAME), nitric oxide (NO) synthase inhibitor, reduced the PACAP-inhibitory response, and the joint application of apamin plus L-NAME produced additive effects. …
Erythropoietin and Myocardial Infarction
2012
Erythropoietin (EPO) has the potential to improve ischemic tissue by mobilizing endothelial progenitor cells and enhancing neovascularization. We hypothesized that combining EPO with human chorionic gonadotrophin (hCG) would improve post–myocardial infarction (MI) effects synergistically.
Tentative immunohistochemical demonstration of melatonin in the rat pineal gland
1977
In the present study an attempt was made to demonstrate melatonin in the rat pineal gland by means of immunohistochemistry. The anti-body used was raised against 5-methoxy-N-acetyltryptophan which is chemically similar to melatonin. Specific fluorescence was demonstrable only in pineals from rats killed during the night, when melatonin formation is high. It was restricted to parenchymal cells lying in a marginal zone of the organ. These results are discussed in relation to a subdivision of the pineal parenchyma into cortical and medullary areas.
Circadian and photoperiodic correlation between the number of pineal gland synaptic ribbons and serum melatonin levels in the rat.
1987
A study is made of the number of pineal gland synaptic ribbons in 35 maleWistar rats over a 24-hour period during the months of September and February, in correlation to the serum melatonin levels during the same periods and photophases.The results of the study confirm those reported by others authors and suggest that the synaptic ribbons may be the stimuli-transmitting organs facilitating pineal secretory function.
Neuropeptide Y: distribution of immunoreactivity and quantitative analysis in diencephalic structures and cerebral cortex of dwarf hamsters under dif…
1995
The distribution of neuropeptide Y-like immunoreactivity (NPY-LI) was investigated by immunohistochemistry and radioimmunoassay (RIA) in the brain of the Djungarian hamster (Phodopus sungorus) held under either long or short photoperiods. In the diencephalic and telencephalic structures studied, distinct patterns of NPY-LI were basically consistent in male and female animals of both groups. NPY levels detected by RIA from tissue samples taken at six time points throughout the 24-hour cycle were in the range of 15-60 pmol/mg protein in the diencephalon or below 5 pmol/mg protein in cerebral cortex. In the diencephalon, immunoreactive structures were seen in the preoptic, peri- and paraventri…
Immunohistochemical evidence for the presence of peptides derived from proenkephalin, prodynorphin and proopiomelanocortin in the guinea pig pineal g…
1988
By using a plethora of region-specific antisera, this light microscopic immunohistochemical study revealed that derivatives from the three opioid precursors, i.e. proenkephalin, prodynorphin and proopiomelanocortin are differentially distributed in the pineal gland of guinea pig. Various molecular forms of immunoreactive opioid peptides derived from proenkephalin or prodynorphin were present in a minority of pinealocytes as well as in nerves. In contrast to this dual distribution pattern of opioid-active peptides, the opioid-inactive derivative from proopiomelanocortin, alpha-melanocyte stimulating hormone, was exclusively present in a large proportion of pinealocytes. A multiple and differ…
Synaptic ribbons of the rat pineal gland: responses to in-vivo and in-vitro treatment with inhibitors of protein synthesis.
1990
To elucidate the role of protein synthesis in the nocturnal increase of synaptic ribbons in the rat pineal gland, actinomycin-D, which inhibits transcription, and cycloheximide, an inhibitor of translation, were used. To assure that the drugs were effective and to relate morphological changes to pineal biosynthetic phenomena, the activity of N-acetyltransferase and levels of pineal indoleamine were measured. Results of in-vivo, short-term and long-term treatment with either drug suggest that transcription of proteins related to synaptic ribbon formation occurs during the first half of the light phase, whereas translation takes place during the first few hours of the dark phase. In contrast,…
Ethanol Modulates Corticotropin Releasing Hormone Release From the Rat Hypothalamus: Does Acetaldehyde Play a Role?
2010
BACKGROUND AND METHODS Ethanol (EtOH) activates hypothalamic-pituitary-adrenal (HPA) axis, resulting in adrenocorticotropin hormone, glucocorticoid release, and in modifications of the response of the axis to other stressors. The initial site of EtOH action within the HPA system seems to be the hypothalamus. Thus, to determine the mechanisms responsible for these effects, we investigated: (i) whether EtOH was able to release corticotrophic releasing hormone (CRH) from incubated hypothalamic explants; (ii) whether acetaldehyde (ACD), its first metabolite formed in the brain by catalase activity, might play a role in EtOH activity. To this aim, rat hypothalamic explants were incubated with: (…
Treatment of cryptorchidism with a potent analog of gonadotropin-releasing hormone.
1978
Pernasal therapy of cryptorchidism with D-Leu6-des-Gly10-gonadotropin-releasing hormone ethylamide (D-Leu6-des-Gly10-GnRH-EA), a potent, long-acting GnRH analog, was attempted. Eleven prepubertal cryptorchid boys received between 25 microgram once daily and 25 to 50 microgram twice daily for 5 to 12 weeks. Complete testicular descent was achieved in 4 of the 11 boys. GnRH tests (1.5 microgram/kg intravenously), conducted in six boys before treatment, after 4 weeks of treatment, and in 2 boys 3 months after treatment, did not reveal changes in gonadotropin secretion indicative of precocious puberty or of decreased hypophyseal sensitivity to GnRH. Antibodies to the GnRH analog or to GnRH coul…
Fos-related antigen 2 (Fra-2) memorizes photoperiod in the rat pineal gland
2004
As the physiological role of fos-related antigen-2 (Fra-2) is largely unknown and since the pineal plays an important role in the photoperiodic control of the body, we have tested the hypothesis that Fra-2 expression is photoperiod-dependent and may be involved in imprinting photoperiod on the pineal gland and the body as a whole. To this end, we have investigated Fra-2 mRNA expression and Fra-2 protein expression under various light/dark (LD) cycles. A clear nocturnal increase occurs for both monitored parameters under all photoperiodic conditions studied. The level of Fra-2 protein expression clearly depends on photoperiod, because the amount of protein at dark onset and during the night …