Immunocytochemical identification and localization of peptide hormones in the gastro-entero-pancreatic (GEP) endocrine system of the mouse and a stomachless fish, Barbus conchonius

A large number of antisera mainly raised against mammalian hormones are tested immunocytochemically on the GEP-endocrine system of mouse and fish (Barbus conchonius). The endocrine pancreas of mouse and fish appeared to contain the same four endocrine cell types; insulin-, glucagon-, PP- and somatostatin-immunoreactive cells. In mouse about 13 GEP endocrine cell types are distinguished: 1. insulin-, 2. somatostatin-, 3. glucagon-, 4. PP-, 5. (entero)glucagon-/PP-like, 6. CCK-like, 7. substance P-, 8. neurotensin-, 9. VIP-, 10. gastrin-, 11. secretin-, 12. beta-endorphin-, 13. serotonin-immunoreactive cells. Based on this and a previous study at least 13 GEP endocrine cell types seems to be present in stomachless fish: 1-9 as described for mouse, 10. (entero)glucagon-like, 11. met-enkephalin, 12. VIP-like, 13. unspecific immunoreactive endocrine cells. Coexistence of glucagon and PP-like peptides is found in the gut and pancreas of mice and in the gut of B. conchonius. In mouse pancreas and fish gut, endocrine cells showing only PP- or glucagon-like immunoreactivity are found too. In mouse stomach some endocrine cells showing only PP-immunoreactivity are demonstrated. In the same region coexistence of C-t-gastrin- and FMRF-amide-immunoreactivity is found in endocrine cells. The importance of these phenomena are discussed. Enteric nerves immunoreactive with antisera raised against substance P and GRP are found in mouse, against somatostatin and met-enkephalin in both mouse and fish and against VIP in fish.     

Exercise-induced swelling of rat soleus muscle: its relationship with intramuscular pressure

Exercise-induced tissue swelling and its possible consequence for tissue pressure were studied in rat soleus muscle. Rats ran for 75 min on a belt with a 10 degree positive incline. Wet weights of cryofixed soleus muscles were increased at 3 (16%), 6 (28%), 9 (16%), and 24 (16%) h after running compared with those of nonexercised controls. The transient increase in muscle wet weight correlated in time with an increase in muscle volume. Muscle fiber swelling accounted for most of the muscle swelling in absolute terms because of the large proportion (approximately 90%) of the muscle volume composed of fibers, but swelling of the interstitium was about twofold larger than fiber swelling per unit area. Muscle fiber degeneration was most frequently found at the end of the observation period, i.e., 24 h after running. The muscle swelling was not associated with an increase in intramuscular pressure. During the postexercise measuring period (18 min to 24 h after exercise), intramuscular pressures of exercised rats (1.3 +/- 0.3 mm Hg) did not differ significantly from control values (1.0 +/- 0.2 mm Hg). These findings indicate that increased intramuscular pressure is not responsible for the muscle fiber degeneration found in rat soleus muscle 24 h after endurance running.     

Cardiovascular responses in paraplegic subjects during arm exercise

The purpose of this study was to examine cardiovascular responses during arm exercise in paraplegics compared to a well-matched control group. A group of 11 male paraplegics (P) with complete spinal cord-lesions between T6 and T12 and 11 male control subjects (C), matched for physical activity, sport participation and age performed maximal arm-cranking exercise and submaximal exercise at 20%, 40% and 60% of the maximal load for each individual. Cardiac output (Qc) was determined by the CO2 rebreathing method. Maximal oxygen uptake was significantly lower and maximal heart rate (fc) was significantly higher in P compared to C. At the same oxygen uptakes no significant differences were observed in Qc between P and C; however, stroke volume (SV) was significantly lower and fc significantly higher in P than in C. The lower SV in P could be explained by an impaired redistribution of blood and, therefore, a reduced ventricular filling pressure, due to pooling of venous blood caused by inactivity of the skeletal muscle pump in the legs and lack of sympathetic vasoconstriction below the lesion. In conclusion, in P maximal performance appears to have been limited by a smaller active muscle mass and a lower SV despite the higher fc,max. During submaximal exercise, however, this lower SV was compensated for by a higher fc and, thus at the same submaximal oxygen uptake, Qc was similar to that in the control group.     

Effect of a pulsating anti-gravity suit on peak exercise performance in individual with spinal cord injuries

The aim of this study was to examine effects of a pulsating pressure anti-gravity suit on the peak values of oxygen uptake (VO2) and power during maximal arm exercise in spinal-cord-injured (SCI) individuals. Five well-trained SCI men (with lesions at levels between T6 and L1) and seven well-trained able-bodied men (ABC) performed two incremental (10 W x min(-1)) arm-cranking tests. During one test the pressure in the anti-G suit pulsated between 4.7 kPa (35 mmHg) and 9.3 kPa (70 mmHg) every 2 s (PPG+), during the other test (PPG-) all the subjects wore the anti-G suit in a deflated state. Tests were performed in a counter-balanced order. Peak VO2 in SCI was 1 ml x kg(-1) x min(-1) lower during PPG+ compared to PPG- (P = 0.05). Peak power and peak heart rate were not significantly different during PPG+ compared to PPG-. These results would suggest that no increase in work capacity can be obtained with a pulsating pressure anti-gravity suit in either SCI or ABC.     

Coexistence of pancreatic polypeptide (PP)-and glucagon-immunoreactivity in pancreatic endocrine cells of mouse

Immunocytochemical double staining techniques were used to study PP- and glucagon-like-immunoreactivity in pancreatic endocrine cells of mouse. An antiserum against FMRFamide appeared to react with all PP-immunoreactive endocrine cells. With fluorescence microscopy most PP/FMRFamide-immunoreactive cells also showed glucagon-immunoreactivity, but cells containing only PP- or glucagon-like substances were found as well. The proportion of cells containing PP-, glucagon, and both immunoreactivities varied strongly from islet to islet in all parts of the pancreas. Using an electron microscopical immunogold double staining procedure on Lowicryl-embedded pancreas, PP/FMRFamide- and glucagon-immunoreactivity appeared to be present in the majority of endocrine A cells; both immunoreactivities were randomly distributed within the granules of these cells. Cells containing only PP/FMRFamide- or glucagon-immunoreactivity were also found. Glucagon- and a faint FMRFamide-immunoreactivity was also observed in osmicated epon-embedded tissue. Independent of their immunoreactivity all positive cells showed the same round electron dense secretory granules.     

Immunocytochemical identification and localization of peptide hormones in the gastro-entero-pancreatic (GEP) endocrine system of the mouse and a stomachless fish,Barbus conchonius

Summary A large number of antisera mainly raised against mammalian hormones are tested immunocytochemically on the GEP-endocrine system of mouse and fish (Barbus conchonius). The endocrine pancreas of mouse and fish appeared to contain the same four endocrine cell types; insulin-, glucagon-, PP- and somatostatin-immunoreactive cells.In mouse about 13 GEP endocrine cell types are distinguished 1. insulin-, 2. somatostatin-, 3. glucagon-, 4. PP-, 5. (entero)glucagon-/PP-like, 6. CCK-like, 7. substance P-, 8. neurotensin-, 9. VIP-, 10. gastrin-, 11. secretin-, 12. -endorphin-, 13. serotonin-immunoreactive cells.Based on this and a previous study at least 13 GEP endocrine cell types seems to be present in stomachless fish: 1–9 as described for mouse, 10. (entero)glucagon-like, 11. met-enkephalin, 12. VIP-like, 13. unspecific immunoreactive endocrine cells.Coexistence of glucagon and PP-like peptides is found in the gut and pancreas of mice and in the gut of B. conchonlus. In mouse pancreas and fish gut, endocrine cells showing only PP-or glucagon-like immunoreactivity are found too. In mouse stomach some endocrine cells, showing only PP-immunoreactivity are demonstrated. In the same region coexistence of C-1-gastrin-and FMRF-amide-immunoreactivity is found in endocrine cells. The importance of these phenomena are discussed.Enteric nerves immunoreactive with antisera raised against substance P and GRP are found in mouse, against somatostatin and met-enkephalin in both mouse and fish and against VIP in fish.In honour of Prof. P. van Duijn     

Coexistence of pancreatic polypeptide (PP)-and glucagon-immunoreactivity in pancreatic endocrine cells of mouse

Summary Immunocytochemical double staining techniques were used to study PP- and glucagon-like-immunoreactivity in pancreatic endocrine cells of mouse. An antiserum against FMRFamide appeared to react with all PP-immunoreactive endocrine cells. With fluorescence microscopy most PP/FMRFamide-immunoreactive cells also showed glucagon-immunoreactivity, but cells containing only PP-or glucagon-like substances were found as well. The proportion of cells containing PP-, glucagon, and both immunoreactivities varied strongly from islet to islet in all parts of the pancreas.Using an electron microscopical immunogold double staining procedure on Lowicryl-embedded pancreas, PP/FMRFamide-and glucagon-immunoreactivity appeared to be present in the majority of endocrine A cells; both immunoreactivities were randomly distributed within the granules of these cells. Cells containing only PP/FMRFamide-or glucagon-immunoreactivity were also found. Glucagon-and a faint FMRFamide-immunoreactivity was also observed in osmicated epon-embedded tissue. Independent of their immunoreactivity all positive cells showed the same round electron dense secretory granules.