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Effects of VIP on gastric and duodenal muscle: A comparison with other neuropeptides and -transmitters, ATP and electrical field stimulation
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IMMUNOCYTOCHEMICAL DEMONSTRATION OF FMRFAMIDE-LIKE IMMUNOREACTIVITY LIVER FLUKE, FASCIOLA HEPATICA
IN THE
R.M. MAGEE, I. FAIRWEATHER, C.F. JOHNSTON*, D.W. HALTON, C. SHAW* and K.D. BUCHANAN*, Departments of Biology and *Medicine, The Queen's University of Belfast, Belfast BT7 INN, Northern Ireland FMRFamide, a molluscan cardioexcitatory peptide, is one of the few native invertebrate peptides to have been fully characterised. It has a wide phylogenetic distribution; in lower metazoans it has been documented in coelenterates and a number of free-living and parasitic platyhelminths. In the present study, FMRFamide immunoreactivity (IR) has been localised in the nervous system of 3 life cycle stages of the liver fluke. Wholemount preparations of metacercariae and juveniles, as well as cryostat sections of mature adult flukes, have been examined by the indirect immunofluorescence technique, using an antiserum raised to FMRFamide. IR was obtained throughout the CNS, in cell bodies (predominantly bipolar in type) and nerve fibres associated with the main anterior ganglia, the longitudinal nerve cords and their commissures. In the PNS, IR occurred in nerve plexuses supplying the sub-tegumental musculature, the suckers and the thin muscular wall of the ootype. A number of immunoreactive flask-shaped cells were also observed amongst the Mehlis' gland cells that surround the ootype and whose secretions are involved in egg formation. Controls were carried out using non-immune serum and preabsorption of antiserum (200 ng FMRFamide/ml diluted antiserum). Pre-incubation with bovine pancreatic polypeptide (up to i0 ~g/ml) did not quench the immunostaining with FMRFamide, indicating that there is no crossreactivity between the two peptides. The present results suggest that FMRFamide may act as a neurotransmitter in Fasciola, and play a more regulatory role in controlling egg production.
EFFECTS OF VIP ON GASTRIC AND DUODENAL MUSCLE: A COMPARISON WITH OTHER NEUROPEPTIDES AND -TRANSMITTERS, ATP AND ELECTRICAL FIELD STIMULATION K. MANDREK* and K, MILENOV** 9 * D e p a r t m e n t of Physiology 9 Philipps-Universitht~ Deutschhausstral~e 2p D-3550 Marburg t FRG a n d * * I n s t i t u t e of Physiology, Bulgarian Academy of Sciences, BG-I 113 Sofia, Bulgaria Mechanical a c t i v i t y was r e c o r d e d in i s o l a t e d muscle p r e p a r a t i o n s from t h e c i r c u l a r and longitudinal layers of porcine stomach and duodenum which c a n b e t a k e n as a good model for human ones, Vasoactive i n t e s t i n a l p e p t i d e (VIP, 10 -10 - 10 -7 tool/l) inhibited t h e spontaneous tonic and rhythmic a c t i v i t y . VIP had l i t t l e e f f e c t on t h e d o s e / r e s p o n s e curves for a c e t y l c h o l i n e (ACh) and s e r o t o n i n , b u t t h o s e for s u b s t a n c e P, bombesin, h i s t a m i n e and for t h e e x c i t a t o r y e f f e c t s of bradykinin w e r e s h i f t e d t o t h e r i g h t w i t h a strong suppression of t h e maximum responses. E l e c t r i c a l field stimulation (EFS, 12 V~ 0.5 msec, 10 cps for $ sec), like a p p l i c a t i o n of VIP, produced a n inhibition which was most p r o m i n e n t in circular duodenum strips. T h e r e f o r % this p r e p a r a t i o n was i n v e s t i g a t e d in more detail. Neither t h e inhibitory e f f e c t of VIP nor t h a t of EFS w e r e a f f e c t e d by g u a n e t h i d i n % a t r o p i n e , apamin and methysergide. The pharmacological analysis suggests t h a t t h e t r a n s m i t t e r system is n e i t h e r c h o l i n e r g i c , nor a d r e n e r g i c , nor s e r o t o n e r g i c , nor purinergic (ATP had no inhibitory effect). One of t h e most likely c a n d i d a t e s for a n inhibitory t r a n s m i t t e r is VIP. First e x p e r i m e n t s with a n t i s e r u m t o VIP, however, did not support this hypothesis. VIP a n t i s e r u m reduced t h e spontaneous t o n e of duodenal strips. A f t e r r e s t o r a t i o n of normal t o n e by ACh a p p l i c a t i o % EFS induced r e l a x a t i o n of a b o u t normal size.
IMMUNOCYTOCHEMICAL DEMONSTRATION OF FMRFAMIDE-LIKE IMMUNOREACTIVITY LIVER FLUKE, FASCIOLA HEPATICA
IN THE
R.M. MAGEE, I. FAIRWEATHER, C.F. JOHNSTON*, D.W. HALTON, C. SHAW* and K.D. BUCHANAN*, Departments of Biology and *Medicine, The Queen's University of Belfast, Belfast BT7 INN, Northern Ireland FMRFamide, a molluscan cardioexcitatory peptide, is one of the few native invertebrate peptides to have been fully characterised. It has a wide phylogenetic distribution; in lower metazoans it has been documented in coelenterates and a number of free-living and parasitic platyhelminths. In the present study, FMRFamide immunoreactivity (IR) has been localised in the nervous system of 3 life cycle stages of the liver fluke. Wholemount preparations of metacercariae and juveniles, as well as cryostat sections of mature adult flukes, have been examined by the indirect immunofluorescence technique, using an antiserum raised to FMRFamide. IR was obtained throughout the CNS, in cell bodies (predominantly bipolar in type) and nerve fibres associated with the main anterior ganglia, the longitudinal nerve cords and their commissures. In the PNS, IR occurred in nerve plexuses supplying the sub-tegumental musculature, the suckers and the thin muscular wall of the ootype. A number of immunoreactive flask-shaped cells were also observed amongst the Mehlis' gland cells that surround the ootype and whose secretions are involved in egg formation. Controls were carried out using non-immune serum and preabsorption of antiserum (200 ng FMRFamide/ml diluted antiserum). Pre-incubation with bovine pancreatic polypeptide (up to i0 ~g/ml) did not quench the immunostaining with FMRFamide, indicating that there is no crossreactivity between the two peptides. The present results suggest that FMRFamide may act as a neurotransmitter in Fasciola, and play a more regulatory role in controlling egg production.
EFFECTS OF VIP ON GASTRIC AND DUODENAL MUSCLE: A COMPARISON WITH OTHER NEUROPEPTIDES AND -TRANSMITTERS, ATP AND ELECTRICAL FIELD STIMULATION K. MANDREK* and K, MILENOV** 9 * D e p a r t m e n t of Physiology 9 Philipps-Universitht~ Deutschhausstral~e 2p D-3550 Marburg t FRG a n d * * I n s t i t u t e of Physiology, Bulgarian Academy of Sciences, BG-I 113 Sofia, Bulgaria Mechanical a c t i v i t y was r e c o r d e d in i s o l a t e d muscle p r e p a r a t i o n s from t h e c i r c u l a r and longitudinal layers of porcine stomach and duodenum which c a n b e t a k e n as a good model for human ones, Vasoactive i n t e s t i n a l p e p t i d e (VIP, 10 -10 - 10 -7 tool/l) inhibited t h e spontaneous tonic and rhythmic a c t i v i t y . VIP had l i t t l e e f f e c t on t h e d o s e / r e s p o n s e curves for a c e t y l c h o l i n e (ACh) and s e r o t o n i n , b u t t h o s e for s u b s t a n c e P, bombesin, h i s t a m i n e and for t h e e x c i t a t o r y e f f e c t s of bradykinin w e r e s h i f t e d t o t h e r i g h t w i t h a strong suppression of t h e maximum responses. E l e c t r i c a l field stimulation (EFS, 12 V~ 0.5 msec, 10 cps for $ sec), like a p p l i c a t i o n of VIP, produced a n inhibition which was most p r o m i n e n t in circular duodenum strips. T h e r e f o r % this p r e p a r a t i o n was i n v e s t i g a t e d in more detail. Neither t h e inhibitory e f f e c t of VIP nor t h a t of EFS w e r e a f f e c t e d by g u a n e t h i d i n % a t r o p i n e , apamin and methysergide. The pharmacological analysis suggests t h a t t h e t r a n s m i t t e r system is n e i t h e r c h o l i n e r g i c , nor a d r e n e r g i c , nor s e r o t o n e r g i c , nor purinergic (ATP had no inhibitory effect). One of t h e most likely c a n d i d a t e s for a n inhibitory t r a n s m i t t e r is VIP. First e x p e r i m e n t s with a n t i s e r u m t o VIP, however, did not support this hypothesis. VIP a n t i s e r u m reduced t h e spontaneous t o n e of duodenal strips. A f t e r r e s t o r a t i o n of normal t o n e by ACh a p p l i c a t i o % EFS induced r e l a x a t i o n of a b o u t normal size.