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Differential distribution of neurotensin, neuromedin N and xenopsin immunoreactivities in the gastrointestinal tract of dog and rat
411 D I F F E R E N T I A L D I S T R I B U T I O N OF NEUROTENSIN, N E U R O M E D I N N AND X E N O P S I N I M M U N O R E A C T I V I T I E S IN THE G A S T R O I N T E S T I N A L T R A C T OF DOG AND RAT C.F. JOHNSTON, C. SHAW and K.D. BUCHANAN, D e p a r t m e n t of Medicine, u n i v e r s i t y of Belfast, Belfast, N. Ireland
The Q u e e n ' s
By means of i m m u n o c y t o c h e m i s t r y , n e u r o t e n s i n (NT), n e u r o m e d i n N (NMN) and x e n o p s i n (XP) i m m u n o r e a c t i v i t i e s (ir) have been localised in the stomach and small intestines of dog and rat. T i s s u e s were fixed in m o d i f i e d susa and p r o c e s s e d to wax. A n t i s e r a e m p l o y e d were NT(6) (C-terminal NT, not c r o s s r e a c t i n g w i t h either NMN or XP), GNMN(II6) (C-terminal NMN, fully c r o s s r e a c t i v e w i t h NT but not XP) and GXP(5) (C-terminal XP, r e q u i r i n g the -pro-trp- sequence). XP-ir was p r e s e n t in antral G - c e l l s of the dog but not the rat and is a t t r i b u t a b l e to c r o s s r e a c t i v i t y w i t h g a s t r i n (i). No NT-ir or NMN-ir was d e t e c t e d at this site. In the ileum of both species all three a n t i s e r a r e a c t e d w i t h the same cells in the crypt epithelium. Additionally, in the rat, N M N - i r was localised in a m i n o r p o p u l a t i o n of e n d o c r i n e cells in the villus tip regions and in the dog, XP-ir was d e t e c t e d in neurones in the sub-mucous plexus. In conclusion, NT, NMN and XP i m m u n o r e a c t i v i t i e s are d i f f e r e n t i a l l y l o c a l i s e d in the g a s t r o i n t e s t i n a l tracts of rat and dog and in the small intestine this may r e p r e s e n t d i f f e r e n t i a l p r e c u r s o r p r o c e s s i n g or the p r e s e n c e of a d d i t i o n a l novel peptides. (i)
J o h n s t o n CF, S h a w C, A r d i l l JES, Sloan J M and B u c h a n a n KD. X e n o p s i n - i m m u n o r e a c t i v i t y in antral G - c e l l s may reside in the N - t e r m i n u s of g a s t r i n 17. H i s t o c h e m i s t r y 1988 (in press).
STIMULATION OF DUODENAL BICARBONATE SECRETION AFTER BLOOD VOLU~4E EXPANSION AN EFFECT MEDIATED BY ATRIAL NATRIURETIC PEPTIDE ? -
C. JONSON 1, L. Ft(NDRIKS 1 and A. PETTERSSON 2. 1 D e p a r t m e n t of Physiology and 2 D e p a r t m e n t of P h a r m a c o l o g y . University of G6teborg, Box 33031, S-400 33 GSteborg, Sweden Hypovolemia is known to inhibit duodenal b i c a r b o n a t e s e c r e t i o n in r a t s via a c t i v a t i o n of t h e splanchnic nerves. A t r i a l n a t r i u r e t i c peptide (ANP) is released a f t e r blood volume expansion and is an i m p o r t a n t r e g u l a t o r of body volume and e l e c t r o l y t e balance. To f u r t h e r i n v e s t i g a t e the i m p o r t a n c e of c e n t r a l h a e m o d y n a m i c s on duodenal b i c a r b o n a t e secretion, the e f f e c t s of h y p e r v o l e m i a and ANP were studied. Duodenal b i c a r b o n a t e s e c r e t i o n were m e a s u r e d by in-situ t i t r a t i o n in chloralosed r a t s before and a f t e r blood volume expansion (10%) with albumin (50 m g / m l i.v.). Animals were divided in groups (n=6): I. Controls, not receiving albumine, 2. Volume expansion (V.E.), 3. V.E. in s p l a n c h n i c o t o m i z e d rats, 4. V.E. in v a g o t o m i z e d and s p l a n c h n i c o t o m i z e d rats, 5. V.E. in r a t s with cut vagal and splanchnic n e r v e s in which a right a t r i a l a p p e n d e c t o m y (reduceses t h e ANP producing ceils) had been p e r f o r m e d 7 days earlier. Duodenal b i c a r b o n a t e s e c r e t i o n (umol/cmxh) Before After 1. C o n t r o l s 18.6+3 19.0+3 (n.s.) 2. Volume Expansion (V.E.) 18.6+_--3 28.6+_--3 (p<0.001) 3. V.E.+Spl-tomy 21.6+2 28.8+3 (p<0.01) 4. V.E.+Vago-+Spl-tomy 12.4+3 18.3+--3 (p<0.01) 5. V.E.+Vago-+Spl-tomy+Atr.Append. 11.1+4 12.0+4 (n.s.) Exogenous ANP i.v. 10 ug (n=6) and 30 ug/kg (n=5) increased bic'-arbonate s e c r e t i o n with 12% (p<0.01) and 25% (p<0.001) respectively. Consequently, t h e d a t a suggest t h a t blood volume expansion i n c r e a s e s duodenal alkaline o u t p u t and t h a t this response, a t l e a s t partly, is m e d i a t e d via the release of ANP.
The Q u e e n ' s
By means of i m m u n o c y t o c h e m i s t r y , n e u r o t e n s i n (NT), n e u r o m e d i n N (NMN) and x e n o p s i n (XP) i m m u n o r e a c t i v i t i e s (ir) have been localised in the stomach and small intestines of dog and rat. T i s s u e s were fixed in m o d i f i e d susa and p r o c e s s e d to wax. A n t i s e r a e m p l o y e d were NT(6) (C-terminal NT, not c r o s s r e a c t i n g w i t h either NMN or XP), GNMN(II6) (C-terminal NMN, fully c r o s s r e a c t i v e w i t h NT but not XP) and GXP(5) (C-terminal XP, r e q u i r i n g the -pro-trp- sequence). XP-ir was p r e s e n t in antral G - c e l l s of the dog but not the rat and is a t t r i b u t a b l e to c r o s s r e a c t i v i t y w i t h g a s t r i n (i). No NT-ir or NMN-ir was d e t e c t e d at this site. In the ileum of both species all three a n t i s e r a r e a c t e d w i t h the same cells in the crypt epithelium. Additionally, in the rat, N M N - i r was localised in a m i n o r p o p u l a t i o n of e n d o c r i n e cells in the villus tip regions and in the dog, XP-ir was d e t e c t e d in neurones in the sub-mucous plexus. In conclusion, NT, NMN and XP i m m u n o r e a c t i v i t i e s are d i f f e r e n t i a l l y l o c a l i s e d in the g a s t r o i n t e s t i n a l tracts of rat and dog and in the small intestine this may r e p r e s e n t d i f f e r e n t i a l p r e c u r s o r p r o c e s s i n g or the p r e s e n c e of a d d i t i o n a l novel peptides. (i)
J o h n s t o n CF, S h a w C, A r d i l l JES, Sloan J M and B u c h a n a n KD. X e n o p s i n - i m m u n o r e a c t i v i t y in antral G - c e l l s may reside in the N - t e r m i n u s of g a s t r i n 17. H i s t o c h e m i s t r y 1988 (in press).
STIMULATION OF DUODENAL BICARBONATE SECRETION AFTER BLOOD VOLU~4E EXPANSION AN EFFECT MEDIATED BY ATRIAL NATRIURETIC PEPTIDE ? -
C. JONSON 1, L. Ft(NDRIKS 1 and A. PETTERSSON 2. 1 D e p a r t m e n t of Physiology and 2 D e p a r t m e n t of P h a r m a c o l o g y . University of G6teborg, Box 33031, S-400 33 GSteborg, Sweden Hypovolemia is known to inhibit duodenal b i c a r b o n a t e s e c r e t i o n in r a t s via a c t i v a t i o n of t h e splanchnic nerves. A t r i a l n a t r i u r e t i c peptide (ANP) is released a f t e r blood volume expansion and is an i m p o r t a n t r e g u l a t o r of body volume and e l e c t r o l y t e balance. To f u r t h e r i n v e s t i g a t e the i m p o r t a n c e of c e n t r a l h a e m o d y n a m i c s on duodenal b i c a r b o n a t e secretion, the e f f e c t s of h y p e r v o l e m i a and ANP were studied. Duodenal b i c a r b o n a t e s e c r e t i o n were m e a s u r e d by in-situ t i t r a t i o n in chloralosed r a t s before and a f t e r blood volume expansion (10%) with albumin (50 m g / m l i.v.). Animals were divided in groups (n=6): I. Controls, not receiving albumine, 2. Volume expansion (V.E.), 3. V.E. in s p l a n c h n i c o t o m i z e d rats, 4. V.E. in v a g o t o m i z e d and s p l a n c h n i c o t o m i z e d rats, 5. V.E. in r a t s with cut vagal and splanchnic n e r v e s in which a right a t r i a l a p p e n d e c t o m y (reduceses t h e ANP producing ceils) had been p e r f o r m e d 7 days earlier. Duodenal b i c a r b o n a t e s e c r e t i o n (umol/cmxh) Before After 1. C o n t r o l s 18.6+3 19.0+3 (n.s.) 2. Volume Expansion (V.E.) 18.6+_--3 28.6+_--3 (p<0.001) 3. V.E.+Spl-tomy 21.6+2 28.8+3 (p<0.01) 4. V.E.+Vago-+Spl-tomy 12.4+3 18.3+--3 (p<0.01) 5. V.E.+Vago-+Spl-tomy+Atr.Append. 11.1+4 12.0+4 (n.s.) Exogenous ANP i.v. 10 ug (n=6) and 30 ug/kg (n=5) increased bic'-arbonate s e c r e t i o n with 12% (p<0.01) and 25% (p<0.001) respectively. Consequently, t h e d a t a suggest t h a t blood volume expansion i n c r e a s e s duodenal alkaline o u t p u t and t h a t this response, a t l e a s t partly, is m e d i a t e d via the release of ANP.