Adrenergic and possible nonadrenergic sources of adenosine 5'-triphosphate release from nerve varicosities isolated from ileal myenteric plexus.
Pretreatment of guinea pigs with 6-hydroxydopamine in vivo for 24 h (250 mg/kg i.p.) reduced the norepinephrine and tyrosine hydroxylase contents of varicosities isolated from ileal myenteric plexus by 91 and 89%, respectively, indicating extensive destruction of noradrenergic varicosities. Destruction appeared to be restricted to noradrenergic varicosities because 5-hydroxytryptamine contents were unaffected. In vivo 6-hydroxydopamine treatment reduced the K+- and veratridine-evoked release of ATP from myenteric varicosities by 56 and 63%, respectively, indicating that much, but not all, of the evoked release of ATP probably originated from noradrenergic varicosities. Pretreatment of guinea pigs with 5 mg/kg of reserpine i.p. depleted norepinephrine contents of isolated varicosities by 90% but did not significantly reduce K+- or veratridine-evoked release of ATP, suggesting that the exocytotic release process was unaffected by reserpine. Selective destruction of serotonergic varicosities by treatment of guinea pigs with 50 mg/kg of desmethylimipramine i.p. followed by 40 mg/kg of 5,7-dihydroxytryptamine s.c. failed to diminish K+- or veratridine-evoked release of ATP from myenteric varicosities, indicating that the nonadrenergic release of ATP did not arise from serotonergic varicosities.
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D006168:Guinea Pigs; D006892:Hydroxydopamines / Q000494:pharmacology; D007082:Ileum / Q000294:innervation; D066298:In Vitro Techniques; D009197:Myenteric Plexus / Q000378:metabolism*; D009638:Norepinephrine / Q000032:analysis / Q000502:physiology*; D016627:Oxidopamine; D011188:Potassium / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D012701:Serotonin / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*; D013574:Synaptosomes / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
D006892:Hydroxydopamines; D012701:Serotonin; D014701:Veratridine; D012110:Reserpine; D016627:Oxidopamine; D000255:Adenosine Triphosphate; D011188:Potassium; D009638:Norepinephrine