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Originaltitel:
Der Einfluß von Adenosinen auf den aszendierenden Reflex im ileum der Ratte 
Übersetzter Titel:
Modulatory effect of adenosins on the ascending neural reflex of the rat ileum 
Jahr:
2001 
Dokumenttyp:
Dissertation 
Institution:
Fakultät für Medizin 
Betreuer:
Allescher, Hans-Dieter (ad. Prof. Dr.) 
Gutachter:
Neumeier, Dieter (Prof. Dr.); Classen, Meinhard (Prof. Dr. Drs. h.c.); Univ.-Prof.Dr.Drs.h.c.(Univ.Istanbul/Türkei; UMF Iassy (Univ. Athen)) 
Format:
Text 
Sprache:
de 
Fachgebiet:
MED Medizin 
Stichworte:
Adenosin; Purine; aszendierender Reflex 
Übersetzte Stichworte:
adenosine; purines; ascending neural reflex 
Kurzfassung:
Endogene Adenosine sind Transmitterstoffe, die die Aktivität von enterischen Neuronen über unterschiedliche Rezeptoren (unter anderem A1- und A2-Rezeptoren) regulieren können. Ziel dieser Arbeit war es, den Einfluß endogener Adenosine und die Rolle der Adenosin A1- und A2-Rezeptoren beim aszendierenden peris- taltischen Reflex der Ratte zu untersuchen. Dazu wurden Rattendünndarmsegmente am aboralen Ende elektrisch stimuliert und die orale Reflexantwort mittels intraluminaler Druckmessung registr...    »
 
Übersetzte Kurzfassung:
The aim of the present study was to investigate the role of adenosins and ATP on the ascending neural pathway in the rat ileum. The ascending neural pathway was activated by anal electrical stimulation of the intrinsic nerves. The excitatory contractile response was recorded by perfused manometry 2 and 4 cm orally to the stimulation site and the area under the curve was determined. The adenosine A1-agonist N6-cyclopentyladenosin(CPA 10-14 - 10-8 M)applied exogenously caused a dose-dependent stimulation of the contractile response (10-14M: 142%, 10-12M: 165%, 10-10M: 192%, 10-8M: 209%, p<0,01), which could be dose-dependently reversed by the selective A1-antagonist 8-cyclopentyl-1,3-dipropylxanthin (DPCPX 10-7 - 10-6 M), but not by the A2-antagonist 3,7-Dimethyl-1-propargylxanthin (DMPX). DPCPX alone caused a dose-dependent inhibition of the the reflex induced contractions (IC50 2*10-7M), however it also induced spontaneous activity. The A2-agonist 5'-(N-Cyclopropyl)carboxamidoadenosin (CPCA) inhibited the reflex induced contractions (10-9M: 101%, 10-8M: 81%, 10-6M: 65%) and this effect was reversed by the A2-antagonist 3,7-Dimethyl-1-propargylxanthin (DMPX). The A2-antagonist DMPX (10-13 - 10-11 M) given alone increased the reflex responses. The ATP-analogue a,ß-methylen-ATP caused a slight inhibition of the reflex induced responses (10-7M: 70%, 10-5M: 64%, 10-4M: 43%). On the other hand the P2-antagonist reactive blue (10-6M: 130%, 10-5M: 151%, 10-4M:168%) and the potassium channel antagonist apamin (10-8M: 155%, 10-7M: 288%), which has been shown to block ATP-induced inhibition, caused a potent stimulation of the reflex response. These results demonstrate that endogenous adenosins acting on A2 receptors and endogenous purines acting on P2-receptors exert an inhibitory tone within the ascending neural pathway of the rat ileum. On the contrary adenosins can promote the ascending reflex via action on A1 receptors. These receptors might also be involved in the regulation of spontaneous peristaltic activity in the rat ileum. 
Veröffentlichung:
Universitätsbibliothek der TU München 
Mündliche Prüfung:
29.01.2001 
Dateigröße:
1099519 bytes 
Seiten:
153 
Letzte Änderung:
27.06.2005