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Titolo:
EVIDENCE FOR A STRYCHNINE-SENSITIVE MECHANISM AND GLYCINE RECEPTORS INVOLVED IN THE CONTROL OF URETHRAL SPHINCTER ACTIVITY DURING MICTURITION IN THE CAT
Autore:
SHEFCHYK SJ; ESPEY MJ; CARR P; NANCE D; SAWCHUK M; BUSS R;
Indirizzi:
UNIV MANITOBA,DEPT PHYSIOL,730 WILLIAM AVE WINNIPEG MB R3E 3J7 CANADA UNIV MANITOBA,DEPT PATHOL WINNIPEG MB R3T 2N2 CANADA
Titolo Testata:
Experimental Brain Research
fascicolo: 3, volume: 119, anno: 1998,
pagine: 297 - 306
SICI:
0014-4819(1998)119:3<297:EFASMA>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT SPINAL-CORD; CENTRAL-NERVOUS-SYSTEM; DECEREBRATE CAT; INHIBITORY INTERNEURONS; INTRATHECAL BACLOFEN; SACRAL MOTONEURONS; CENTRAL SYNAPSES; PUDENDAL NERVE; FEMALE CAT; AFFERENT;
Keywords:
SPINAL INHIBITION; INTERNEURONS; MICTURITION; BLADDER-SPHINCTER DYSSYNERGIA; CAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
56
Recensione:
Indirizzi per estratti:
Citazione:
S.J. Shefchyk et al., "EVIDENCE FOR A STRYCHNINE-SENSITIVE MECHANISM AND GLYCINE RECEPTORS INVOLVED IN THE CONTROL OF URETHRAL SPHINCTER ACTIVITY DURING MICTURITION IN THE CAT", Experimental Brain Research, 119(3), 1998, pp. 297-306

Abstract

Micturition in the decerebrate cat is characterized by a coordinated bladder contraction and a simultaneous decrease in external urethral sphincter (EUS) efferent activity. Without the suppression of EUS activity, voiding is significantly impaired, resulting in a state sometimesreferred to as bladder-sphincter dyssynergia. The aim of the present study was to determine whether glycinergic inhibition contributes to the suppression of EUS activity during micturition evoked by bladder distension or electrical stimulation of the pontine micturition center (PMC) in decerebrate cats. Using subconvulsive intravenous doses of strychnine (0.1-0.24 mg/kg), we examined changes in bladder and EUS electroneurographic (ENG) activity during micturition, Following subconvulsive doses of strychnine, tonic EUS ENG activity increased during bladder filling in five of six animals. In the presence of strychnine, it was possible to evoke reflex bladder contractions of similar duration and peak pressure to those observed before strychnine administration. However, there was an absence of suppression of EUS ENG activity duringthe bladder contractions in all the animals. To determine whether thechanges in sphincter activity could be due to strychnine acting at glycine receptors on EUS motoneurons, sacral spinal tissue was processedfor a structural protein (gephyrin) associated with the glycine receptor. Motoneurons in Onuf's nucleus in S1 were identified using cholineacetyltransferase immunohistochemistry and subsequently processed with a gephyrin monoclonal antibody. Abundant gephyrin labeling was evident throughout Onuf's nucleus. Since Onuf's nucleus is made up of EUS and other motoneuron populations, a sample of antidromically identifiedurethral and anal sphincter motoneurons were intracellularly labeled with tetramethylrhodamine dextran (TMR-D) and then processed with the gephyrin antibody. Using dual-beam confocal microscopy, gephyrin immunoreactivity was observed on the soma and proximal processes of individual EUS motoneurons in both male and female animals. It was concluded that a strychnine-sensitive mechanism contributes to the suppression of sphincter activity normally observed during voiding. Although glycinergic inhibition may affect several components of the circuitry responsible for micturition, it appears that the suppression of EUS motoneurons during micturition may be partly due to a direct glycinergic inhibition of the EUS motoneurons.

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Documento generato il 04/04/20 alle ore 21:30:59