Effects of chronic l-DOPA administration on neurogenic and endothelium-dependent relaxation responses in rabbit corpus cavernosum.
Pharmacol Rep
; 68(5): 926-34, 2016 Oct.
Article
em En
| MEDLINE
| ID: mdl-27362769
ABSTRACT
BACKGROUND:
Dopamine is a crucial central neurotransmitter that plays a fundamental role in the autonomic and somatic components of penile reflexes in animals and humans. Similar to the erectile responses of dopamine, systemic administration of l-DOPA induces yawning and penile erection in some species. The possible effects of l-DOPA on nitric oxide (NO)-dependent and -independent non-adrenergic non-cholinergic (NANC) relaxation responses mediated by electrical field stimulation (EFS) and endothelium-dependent relaxation were investigated in this study.METHODS:
Thirty-two adult albino male rabbits, in two- and four-week-treatment groups, were divided into three subgroups control group (saline-injected) (n=4), 3mg/kg/day (low dose) l-DOPA-injected groups (n=6) and 12mg/kg/day (high dose) l-DOPA-injected groups (n=6). After the intraperitoneal injection treatments, the corpus cavernosum tissues were placed in organ bath chambers. The EFS-mediated responses, and the concentration-response curve to carbachol, sodium nitroprusside (SNP), sildenafil were assessed.RESULTS:
The two-week treatment with high-dose l-DOPA decreased the NO-dependent NANC relaxation responses, while there was no change in the low-dose two- and four-week treatment groups. The NO-independent NANC relaxation responses in the two-week groups decreased, and the responses in the four-week groups were unchanged when compared to the controls. The relaxation responses to carbachol showed no differences among all groups except for the high-dose four-week l-DOPA group. The relaxation responses of SNP and sildenafil were increased in all of the treatment groups when compared to the controls.CONCLUSIONS:
The observed increases in SNP- and sildenafil-induced responses, along with the decreased EFS-mediated responses, suggest increased sensitivity in the NO-signalling pathway following l-DOPA administration.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Pênis
/
Ereção Peniana
/
Levodopa
/
Endotélio
/
Neurogênese
/
Relaxamento Muscular
Limite:
Animals
Idioma:
En
Revista:
Pharmacol Rep
Assunto da revista:
FARMACOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article