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Involvement of 5-hydroxytryptamine1A receptors in the modulation of micturition reflexes in the anesthetized rat.
Involvement of 5-hydroxytryptamine1A receptors in the modulation of micturition reflexes in the anesthetized rat.
- Source :
-
The Journal of pharmacology and experimental therapeutics [J Pharmacol Exp Ther] 1992 Jul; Vol. 262 (1), pp. 181-9. - Publication Year :
- 1992
-
Abstract
- Intravenous administration of the selective 5-hydroxytryptamine (5-HT)1A receptor agonist 8-hydroxy-2-(di-N-propylaminotetralin (8-OH-DPAT) and of a low doses of buspirone elicited the supraspinal micturition reflex (SMR) in urethane-anesthetized rats when the urinary bladder was filled with just a subthreshold volume of saline (threshold conditions). The effect of i.v. 8-OH-DPAT was abolished by hexamethonium or spiroxatrine. When SMR was elicited by bladder distension (suprathreshold conditions), i.v. 8-OH-DPAT increased the frequency of bladder contractions. In threshold conditions, stimulation of SMR was also induced by i.c.v. or by i.t. administration of 8-OH-DPAT and 5-HT but not by topical application of 8-OH-DPAT onto the bladder. Guanethidine pretreatment, which produced detrusor hyperreflexia, antagonized the effect of both i.c.v. and i.t. 8-OH-DPAT. In rats treated with capsaicin as adults, the response to 8-OH-DPAT was unchanged. In rats treated with capsaicin as newborns, instead, the response to i.t. 8-OH-DPAT was abolished and that to i.c.v. 8-OH-DPAT was shifted to higher doses. Pretreatment with 5,7-dihyroxytryptamine did not affect the response to i.t. 8-OH-DPAT but shifted to higher doses the response to i.c.v. 8-OH-DPAT. Intravenous administration of spiroxatrine, methysergide, NAN-190 [1-(2-methoxyphenyl)-4-[4-(2-phtalimido)butyl] piperazine] or high doses of buspirone but not of 1-sulpiride inhibited SMR in suprathreshold conditions. The inhibitory effect of spiroxatrine, NAN-190 and buspirone was not reduced by guanethidine pretreatment. In chronically spinalized animals, i.v. 8-OH-DPAT increased the amplitude of the reflex bladder contractions induced by bladder distension.(ABSTRACT TRUNCATED AT 250 WORDS)
- Subjects :
- 8-Hydroxy-2-(di-n-propylamino)tetralin
Administration, Topical
Aging metabolism
Animals
Antihypertensive Agents pharmacology
Capsaicin pharmacology
Dose-Response Relationship, Drug
Electric Stimulation
Hexamethonium
Hexamethonium Compounds pharmacology
Injections, Intravenous
Injections, Intraventricular
Injections, Spinal
Male
Rats
Rats, Inbred Strains
Tetrahydronaphthalenes administration & dosage
Tetrahydronaphthalenes antagonists & inhibitors
Receptors, Serotonin drug effects
Serotonin Antagonists pharmacology
Tetrahydronaphthalenes pharmacology
Urinary Bladder drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3565
- Volume :
- 262
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The Journal of pharmacology and experimental therapeutics
- Publication Type :
- Academic Journal
- Accession number :
- 1352548