Effects of 5-Hydroxytryptophan on Arterial Blood Pressure, Body Temperature and Tissue Monoamines in the Rat
| Autor: | Allan Rubenson, Matts Henning |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Male
Nialamide Serotonin medicine.medical_specialty Decarboxylase inhibitor Blood Pressure Toxicology Body Temperature 5-Hydroxytryptophan chemistry.chemical_compound Dopamine Internal medicine medicine Animals Aromatic Amino Acid Decarboxylase Inhibitors Pharmacology Aromatic L-amino acid decarboxylase Chemistry Hypothermia Rats Endocrinology Blood pressure Anesthesia Propionates medicine.symptom medicine.drug |
| Zdroj: | Acta Pharmacologica et Toxicologica. 29:145-154 |
| ISSN: | 0001-6683 |
| DOI: | 10.1111/j.1600-0773.1971.tb00601.x |
| Popis: | The mean arterial blood pressure in conscious rats was recorded by means of in-dwelling arterial catheters. DL-5-hydroxytryptophan (5-HTP) 200 mg/kg intraperitoneally lowered the blood pressure significantly after 20 min. Following the administration of the peripheral decarboxylase inhibitor L-α-hydrazino-α-methyl-β-(3,4-dihydroxyphenyl) propionic acid (MK 486) 100 mg/kg intraperitoneally, 5-HTP 200 mg/kg intraperitoneally caused only a slight lowering of the blood pressure after 1–2 hrs. 5-HTP 50 mg/kg given intraperitoneally after a combined pretreatment with a MAO inhibitor (nialamide) 100 mg/kg intraperitoneally and MK 486 100 mg/kg produced characteristic effects on gross behaviour after 20 min. No significant effects of 5-HTP on the blood pressure were observed in these experiments. 5-HTP 200 mg/kg intraperitoneally caused a hypothermia which was prevented by MK 486 100 mg/kg. After pretreatment with nialamide and MK 486 as in the blood pressure experiments, 5-HTP 50 mg/kg produced an initial hypothermia followed by a pronounced rise in body temperature. 5-HTP 200 mg/kg intraperitoneally resulted in a marked accumulation of 5-hydroxytryptamine (5-HT) in the heart and brain. Pretreatment with MK 486 100 mg/kg prevented the increase in heart 5-HT but did not change that in the brain. Brain dopamine (DA) but not brain and heart noradrenaline (NA) decreased significantly. 5-HTP 50 mg/kg after the administration of nialamide and MK 486 increased the brain 5-HT but caused no change in heart 5-HT. Nialamide and MK 486 per se increased brain DA and NA significantly; 5-HTP largely prevented the increase in brain DA but not in brain NA. It is concluded that 5-HTP has a hypothermic and a hypotensive action due to the effect of 5-HT on the extracerebral structures, while the hyperthermic effect may have a central nervous origin. 5-HT formed from 5-HTP lowers brain DA by displacement. |
| Databáze: | OpenAIRE |
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