Celiac Mesenteric Ganglia Research Articles

Nervous control of gastric and pancreatic secretory response to 2-deoxy-D-glucose in the dog.

The relative contribution of the vagus and splanchnic nerves as mediators of the action of 2-deoxy-D-glucose (2-DG) on the stomach and the pancreas is largely unknown. In conscious dogs with gastric and pancreatic fistulas, the effect of 2-DG (100 mg kg-1, given as an intravenous bolus) on gastric acid and pancreatic exocrine secretion was tested before and after bilateral truncal vagotomy and after truncal vagotomy plus celiac and superior mesenteric ganglionectomy (i.e. extrinsic denervation of the stomach and the pancreas). In another set of dogs, only ganglionectomy was performed and the same experiments were done as in the first set of dogs. With the extrinsic nerves intact, 2-DG caused a rapid (within 15 min) and prolonged increase in gastric acid output as well as in pancreatic flow rate, bicarbonate and protein output. Truncal vagotomy abolished the gastric acid and pancreatic secretory response to 2-DG; additional ganglionectomy had no further effect. Ganglionectomy alone did not significantly alter 2-DG-stimulated gastric acid output, pancreatic flow rate and bicarbonate output; protein output, however, was significantly diminished by 57%. These results indicate that (a) intravenous 2-DG is a potent stimulant of gastric acid and pancreatic bicarbonate and protein output; (b) the vagus nerves are the major mediators of the gastric and pancreatic secretory response to 2-DG; (c) the sympathetic nerve fibers running through the celiac and superior mesenteric ganglia are probably not involved in the mediation of the 2-DG-induced gastric acid and pancreatic bicarbonate secretion. The diminished protein response to 2-DG after ganglionectomy is probably due to cut vagal fibers running through these ganglia.

Indices of neurotransmitter synthesis and release in aging sympathetic nervous system

Activities of tyrosine hydroxylase (TH),dopamine-β-hydroxylase (DBH) and choline acetyltransferase (ChAT) were assayed in sympathetic ganglia and adrenal glands of young and aged Fischer-344 rats. The recovery of reserpine-depleted catecholamine stores and catecholamine loss following inhibition of synthesis and intraneuronal degradation also were assessed in sympathetic ganglia of young and aged rats. No age differences were observed in DBH activity of any tissues examined or in the activities of any enzymes in the coeliac-mesenteric ganglion complex. However, TH and ChAT activities were significantly higher in the superior cervical ganglia and adrenal glands of aged rats. In the hypogastric ganglion, only TH activity was higher in the old rats. Recoveries of reserpine-depleted catecholamine stores in the superior cervical and hypogastric ganglia of aged rats were slower than in young rats. Catecholamine loss following inhibition of synthesis and intraneuronal degradation was faster in the superior cervical ganglia but not in the hypogastric ganglia of old rats as compared with young rats. These findings suggest that neurotransmitter synthesis and release are enhanced with age in the superior cervical ganglion. The lack of age-related changes in the hypogastric ganglion might reflect the different cellular composition as well as the physiological role of this ganglion.

Stimulation of pancreatic afferents reflexly activates the cardiovascular system in cats.

Chemical stimulation of afferents from the stomach and gallbladder has been shown reflexly to activate the cardiovascular system. It is not known, however, whether stimulating afferents from the pancreas evoke similar reflex activity. Therefore we recorded the cardiovascular responses in cats anesthetized with methoxyflurane, while we applied capsaicin (200 micrograms/ml) and bradykinin (0.001-1,000 micrograms/ml) to the surface of the pancreas. Topically applying these algesic substances evoked cardiovascular responses that included increases in systemic arterial pressure, heart rate, left ventricular dP/dt at 40-mmHg developed pressure and systemic vascular resistance. Bilateral vagotomy at the level of the diaphragm did not diminish the cardiovascular responses evoked by capsaicin or bradykinin. In contrast, removal of the celiac and superior mesenteric ganglia abolished the cardiovascular responses demonstrated previously when capsaicin or bradykinin was applied to the pancreas. We conclude that afferent endings in the pancreas can be stimulated reflexly to increase cardiovascular function in cats. This reflex activation represents a potential mechanism for eliciting the cardiovascular changes observed during acute pancreatitis, particularly the marked vasoconstriction that may lead to renal failure.

Glucose utilization in sympathetic ganglia of male Fischer-344 rats at different ages.

The relation of glucose utilization to age was studied with the [14C]2-deoxy-D-glucose method in 3 peripheral sympathetic ganglia of conscious male Fischer-344 rats. The hypogastric ganglion, coeliac-mesenteric ganglion complex and superior cervical ganglion were examined in 3-, 12-, 24- and 30-33-month-old animals. Glucose utilization increased significantly between 12 and 30-33 months in the superior cervical ganglion and between 3 and 24 months in the coeliac-mesenteric ganglion complex. No significant, age-related changes were observed in the hypogastric ganglion. In addition, neuron density decreased significantly between 3 and 12 months in the hypogastric ganglion and between 3 and 30-33 months in the coeliac-mesenteric ganglion complex, but no changes were observed in the superior cervical ganglion. Despite the increased glucose utilization in the superior cervical ganglion, heart rate decreased between 12 and 24 months, and mean arterial blood pressure decreased between 24 and 30-33 months. The results suggest that functional activity of some sympathetic ganglia increases in older rats, although end organ effects may be reduced.

Age related increase in catecholamine-containing paraganglia in male Fischer-344 rats.

For identification of paraganglia (PG), samples of para-aortic tissue, tissues containing the coeliac-mesenteric ganglion complex, and the hypogastric ganglia were removed from 3- and 33-month-old male Fischer-344 rats and were processed by the formaldehyde-induced fluorescence method for visualization of catecholamines. Small PG containing 5-30 cells per section were found consistently in young animals. In each of six old rats, large PG containing 500-4000 brightly fluorescent cells per section were detected. Cell counting revealed a 13.5 x increase in number of PG cells between 3- and 33-month-old rats. Microspectrofluorimetric quantitation in old rats showed equal amounts of catecholamines in PG cells and in adrenal medullary cells. Most PG were located in samples from the para-aortic area.

Small granulated cell types in rat superior cervical and coeliac-mesenteric ganglia.

In the rat superior cervical and coeliac-mesenteric ganglia we have observed three types of small granulated (SG) cell: Type I cells are characterised by membrane-bounded cytoplasmic granules with a core of variable, moderate to low electron-density, whose limiting membranes are rounded in profile ranging from 50-150 nm in diameter. Type II SG cells contain numerous highly electron-dense, polymorphic cytoplasmic granules ranging from 100-300 nm in diameter. The haloes of Type II cell granules are variable in shape, and the core is often eccentrically located or fragmented. Type III SG cells contain membrane-bounded granules with a core of variable moderate to low electron-density. In profile these granules appear oblong or circular with average dimensions of 170 x 50 nm. All three SG cell types receive cholinergic-type pre-ganglionic terminals whose afferent nature is confirmed by their degeneration following pre-ganglionic neurectomy. Only Type I cells have been observed to donate efferent synapses to dendrites of principal ganglionic neurones and are thus interneuronal.

Reserpine-induced catecholamine depletion from small cells in rat sympathetic ganglia

Two reserpine dosage schedules were applied to Wistar rats (a) 5 mg/kg i.p. 6 hr before sacrifice and (b) 5 mg/kg i.p. at 36, 24 and 12 hr prior to sacrifice. Control animals were correspondingly sham-injected. The coeliac—mesenteric ganglion complex was removed and processed either for the Falck-Hillarp fluorescence histochemical technique or fixed in glutaraldehyde followed by 3.5% potassium dichromate for a chromaffin-type reaction. After a single reserpine injection there was a statistically significant ( p < 0.001) reduction in the percentage of ‘chromaffin-positive’ cells and a statistically significant ( p < 0.001) increase in the percentage of ‘chromaffin-negative’ cells compared with controls. No obvious reduction in fluorophore emission from small intensely fluorescent (SIF) cells was observed. After prolonged reserpinization (3 × 5 mg/kg) there was a highly significant reduction in the percentage of ‘chromaffin-positive’ small cells and also a significantly lower (by a factor of 2) level of fluorescent emission from SIF cells. The catecholamine-releasing potential of small cells is demonstrated by these results.

Gastric and pancreatic sympathetic denervation in the rat. Technique and results.

The extirpation of the coeliac and superior mesenteric ganglia was found to be a simple and effective method of achieving complete adrenergic denervation of the stomach and pancreas in the rat. Thus, using the formaldehyde fluorescence technique, no remaining adrenergic nerves in these organs could be found after ganglionectomy. The vagus nerves did not significantly contribute to the adrenergic innervation of the stomach and pancreas. Chemical methods revealed minute amounts of noradrenaline in the pancreatic tissue even after complete ganglionectomy. The cellular source of this catecholamine is unknown. Sympathetic denervation of the stomach did not change the gastric acid secretory pattern, as studied with chronic gastric fistula rats.

Motor response of the stomach and small intestine caused by stimulation of the peripheral end of the splanchnic nerve, thoracic sympathetic trunk and spinal roots.

The increased motor response of the gastro-intestinal activity caused by peripheral stimulation of the splanchnic nerve, thoracic sympathetic trunk and its dorsal roots was studied on anesthetized and unanesthetized dogs and toads.1) Peripheral stimulation of the splanchnic nerve and thoracic sympathetic trunk, causes universally inhibition of gastro-intestinal motility and at times, produced augmentation. The conditions capable of producing the motor response in the normal animals are different in the individuals.2) After blocking the coeliac and superior mesenteric ganglia, stimulation of the splanchnic nerve and theracic sympathetic trunk always produce augmentation of the movement. The blockade of these ganglia was the indispensable condition necessary in producing the increased gastro-intestinal motor response by sympathetic stimulation.3) By peripheral stimulation of the dorsal root of the thoracic cord, motor augmentation of gastro-intestinal motility can always be obtained. The motor response is not influenced by the block of the coeliac and superior mesenteric ganglia and the ganglia of the thoracic sympathetic trunk.After a nicotine-solution is injected into the spinal ganglia, stimulation of the dorsal roots has no effect on gastro-intestinal activity.Stimulation of the ventral root of the thoracic, cord always. causes inhibition.After blocking the coeliac and superior mesenteric ganglia, this inhibitory effect almost totally disappears.