Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
6
|
| pubmed:dateCreated |
1991-5-23
|
| pubmed:abstractText |
In order to investigate the potential antagonistic actions of the two main neuroregulators of the somatotropinergic system (GRF-SS-GH-SM axis), growth hormone-releasing factor (GRF) and somatostatin (SS) at the central level, the effects of GRF and SS on locomotor activity (LA) were studied in a computerized system. Male Wistar rats (N = 6-9 per group) received i.p. or i.c.v. GRF(1-44)NH2 or SS(1-14) in doses ranging from 0.1-30 micrograms, and LA was automatically recorded in the OUCEM-86 system (Osaka University Computerized Electronic Maze) for 30-min periods. The peripheral administration of SS (1 microgram, i.p.) did not alter LA, while GRF (1 microgram, i.p.) increased LA from 20.35 +/- 4.18 to 36.25 +/- 6.98 IO/min (p less than 0.005). After central injection, SS (1 microgram; i.c.v.) decreased LA from 31.16 +/- 6.90 to 20.88 +/- 2.82 IO/min (p less than 0.005) and GRF (1 microgram, i.c.v.) increased LA to 47.60 +/- 5.35 IO/min (p less than 0.005). SS- and GRF-induced LA changes were time- and dose-dependent (SS: ED50 = 1.83 nmol, Emax = 6.10 nmol; GRF: ED50 = 99.1 pmol, Emax = 1.98 nmol). The maximum effect of GRF appeared during the first 5 min, showing activity 10-15 sec post-injection, while the lowest activity induced by SS was registered 15-30 min after injection, although a significant reduction in LA was detected 5-10 sec after i.c.v. administration. With doses higher than 10 micrograms (i.c.v.) SS provoked "barrel rotation", tremors and stereotyped behaviors. The GRF-induced hyperkinetic syndrome showed a linear pattern with doses up to 10 micrograms, and a plateau with 10-15 micrograms. Doses higher than 20 micrograms induced convulsion, uncontrolled movements and a high death rate during the following 12-24 h. In conclusion, according to the present results, GRF and SS exert antagonistic effects on LA in a time- and dose-dependent manner, the former stimulating LA, and the latter inhibiting it.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:issn |
0379-0355
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
12
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
425-34
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:1982332-Animals,
pubmed-meshheading:1982332-Attention Deficit Disorder with Hyperactivity,
pubmed-meshheading:1982332-Behavior, Animal,
pubmed-meshheading:1982332-Computer Systems,
pubmed-meshheading:1982332-Growth Hormone-Releasing Hormone,
pubmed-meshheading:1982332-Injections, Intraperitoneal,
pubmed-meshheading:1982332-Injections, Intravenous,
pubmed-meshheading:1982332-Male,
pubmed-meshheading:1982332-Motor Activity,
pubmed-meshheading:1982332-Rats,
pubmed-meshheading:1982332-Rats, Inbred Strains,
pubmed-meshheading:1982332-Somatostatin
|
| pubmed:articleTitle |
Antagonistic effects of growth hormone-releasing factor (GRF) and somatostatin on locomotor activity: GRF-induced hyperkinetic syndrome.
|
| pubmed:affiliation |
Department of Human Physiology, Faculty of Medicine, Madrid Complutense University, Spain.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|