Protein secretion from the cat parotid gland on nerve stimulation

1. The output and composition of proteins in nerve stimulated saliva samples were compared. 2. Protein output upon parasympathetic stimulation was higher than following sympathetic stimulation and was accompanied by an obvious degranulation of acini with the former but not the latter. These events are the converse of those in the rat parotid gland. 3. Superimposition of sympathetic upon parasympathetic stimulation caused an augmented output of salivary protein. 4. Electrophoresis of salivas revealed differences between individual cats in protein composition but not between differently stimulated salivas.     

Effects of parasympathectomy on protein composition of sympathetically evoked parotid saliva in rats

1. Male Wistar rats were given unilateral postganglionic parasympathectomies by sectioning the auriculo-temporal nerve. 2. Analyses of the protein compositions of sympathetically induced saliva from both glands 1 week later revealed changes in the proportions of different secretory proteins, in particular amylase and basic proline-rich proteins were decreased. 3. These results suggest that parasympathetic impulses are required for the normal synthesis of amylase by parotid parenchyma in rats. Basic proline-rich proteins, known to require a sympathetic drive for normal synthesis, appear to require a parasympathetic input as well.     

Immunohistochemical characterisation of sympathetic and parasympathetic pelvic neurons projecting to the distal colon in the male rat

The pelvic ganglia are mixed ganglia containing both sympathetic and parasympathetic neurons that receive spinal input via the hypogastric (lumbar cord) and pelvic nerves (sacral cord), respectively. A recent study has utilised immunohistochemistry against synaptophysin (a protein associated with small vesicles) to visualise the preganglionic terminals in these ganglia. By selectively cutting the hypogastric or pelvic nerves and allowing subsequent terminal degeneration, the populations of parasympathetic and sympathetic preganglionic terminals, respectively, can be visualised. The present study has used this method in conjunction with retrograde labelling of pelvic neurons from the distal colon and double label immunofluorescence against tyrosine hydroxylase and vasoactive intestinal polypeptide (VIP) to identify and characterise the sympathetic and parasympathetic neurons projecting to the distal colon from the major pelvic ganglia of the male rat. Approximately equal numbers of distal colonic-projecting pelvic neurons are sympathetic and parasympathetic. Almost all noradrenergic neurons are sympathetic. Of the VIP neurons that project to the distal colon approximately one third are sympathetic, one third parasympathetic and the remaining third are possibly innervated by both the lumbar and sacral cord. Extrapolation from our results also suggests that the majority of non-noradrenergic neuropeptide Y neurons (which are known to comprise the remainder of the neurons) are parasympathetic. These studies have demonstrated that the pelvic ganglia are a major source of sympathetic innervation to the distal bowel and have further shown that the distal colon is another target for the non-noradrenergic sympathetic neurons of the pelvic ganglia.     

In vivo secretory responses of submandibular glands in streptozotocin-diabetic rats to sympathetic and parasympathetic nerve stimulation

Submandibular gland responses to sympathetic and parasympathetic nerve stimulation were studied in streptozotocin-diabetic rats. Morphologically, the acinar cells in control glands were relatively uniform in size and contained electron-lucent granules. The granular ducts were distinguished by the presence of electron-dense granules. With the exception of intracellular lipid droplets and the presence of a few autophagosomes in diabetic glands, no consistent differences in acinar cell structure were observed. In contrast, the diameter of the granular ducts and the granule content of their cells were less in diabetic glands. At 3 weeks sympathetic flow rate, salivary protein concentration, and total protein output were unaffected by diabetes. Sympathetic flow rate was greater at 3 months, and the concentration of protein in the saliva was lower. In 6-month diabetic rats flow rate remained increased, but protein concentration and total protein output were reduced. The decrease in salivary protein concentration at 3 and 6 months was accompanied by a reduction in secretory granule release from acinar and granular duct cells. No consistent differences in flow rate, protein concentration, protein output, or secretory granule release were observed following parasympathetic stimulation. We conclude that the effects of diabetes on nerve-stimulated flow rate and protein release depend on the duration of diabetes and the type of stimulation, and are independent of one another.     

Effects of varying frequency of sympathetic stimulation on chloride and amylase levels of saliva elicited from rat parotid gland with electrical stimulation of both autonomic nerves.

Simultaneous stimulation of the parasympathetic and sympathetic nerves to the parotid gland of rats elicited saliva at a rate dependent on the frequency of sympathetic stimulation when parasympathetic frequency was maintained at 16 Hz. The flow rate was lowest at 2 Hz (sympathetic), moderate at 5 Hz, and highest at 16 Hz. Cl concentration of the saliva evoked with stimulation of both nerves was highest at the highest frequency and flow rate (maintained at the level of 102 mEq/liter, for 35 min) and lowest at 2 Hz (declining from 40 mEq/liter initially to 28 mEq/liter). With sympathetic nerve stimulation alone, Cl concentration ranged from 27 to 58 mEq/liter when frequency was varied from 2 to 16 Hz, and with parasympathetic stimulation alone (16 Hz), it ranged from 132 to 124 mEq/liter. Amylase concentration of sympathetically elicited saliva was, in contrast, highest at 2 Hz (1.5 times the level at 5 Hz, and twice the level at 16 Hz), and nearly 18-38 times that seen with parasympathetic stimulation alone. The same pattern was found when both nerves were stimulated, and at 2 Hz (sympathetic), amylase concentration was 1.6 times the level at 5 Hz and 2.6 times the level at 16 Hz. When the two nerves were simultaneously stimulated, the total amount of amylase secreted over 35 min was twice as high as that observed with sympathetic nerve stimulation alone, at any frequency. The relation of frequency to norepinephrine concentration was examined. There was no consistent difference in norepinephrine concentration related to variation in frequency of sympathetic stimulation. Only when both nerves were stimulated at 16 Hz was there a statistically significant reduction in norepinephrine concentration of 46%. A relation between frequency of sympathetic stimulation, flow rate, amylase concentration, and Cl concentration was established, but these changes could not be directly correlated with quantitative differences in norepinephrine concentration.     

Cardiac Autonomic Activity During Human Sleep: Analysis of Sleep Stages and Sleep Cycles

In this study characteristics of cardiac functioning were investigated in nine subjects during their nocturnal sleep. The pre-ejection period and the high frequency component of heart rate variability were used as indices of cardiac sympathetic and parasympathetic activity of the autonomic nervous system respectively. Heart rate and the autonomic indices were assessed across physiological determined sleep stages and consecutive temporal sleep cycles. Repeated measures ANOVA analyses indicated a significant pattern of heart rate as a function of sleep stages, which was mirrored by parasympathetic activity. Further, a significant decrease of heart rate as a function of sleep cycles was mirrored by an increase of sympathetic activity. Moreover, non-REM/REM differences revealed a dominant role of parasympathetic activity during sleep stages as well as sleep cycles. These findings demonstrate that sympathetic activity is influenced by time asleep, whereas parasympathetic activity is influenced by the depth of sleep.     

Cardiac Autonomic Activity During Human Sleep: Analysis of Sleep Stages and Sleep Cycles

In this study characteristics of cardiac functioning were investigated in nine subjects during their nocturnal sleep. The pre-ejection period and the high frequency component of heart rate variability were used as indices of cardiac sympathetic and parasympathetic activity of the autonomic nervous system respectively. Heart rate and the autonomic indices were assessed across physiological determined sleep stages and consecutive temporal sleep cycles. Repeated measures ANOVA analyses indicated a significant pattern of heart rate as a function of sleep stages, which was mirrored by parasympathetic activity. Further, a significant decrease of heart rate as a function of sleep cycles was mirrored by an increase of sympathetic activity. Moreover, non-REM/REM differences revealed a dominant role of parasympathetic activity during sleep stages as well as sleep cycles. These findings demonstrate that sympathetic activity is influenced by time asleep, whereas parasympathetic activity is influenced by the depth of sleep.     

Secretory responses in granular ducts and acini of submandibular glands in vivo to parasympathetic or sympathetic nerve stimulation in rats

Summary The roles of sympathetic and parasympathetic nerves in the secretion of saliva from submandibular glands of rats have been tested by electrical stimulation of either nerve for 1 h unilaterally in separate animals. The flows of saliva thereby induced and their protein content were monitored. Structural changes in each gland were assessed by light- and electron microscopy and compared with the unstimulated contralateral control gland, and the extent of the changes was determined morphometrically. Sympathetic nerve stimulation induced a relatively low flow of saliva that was rich in protein and was accompanied by extensive degranulation from both acinar and granular duct cells. In contrast parasympathetic nerve stimulation induced a considerable flow of saliva that had a low protein content and no detectable degranulation occurred from the secretory cells. It is possible, therefore, that some protein in parasympathetic saliva may have arisen from a non-granular pathway.     

Characterization of a neuronal growth factor from mouse heart-cell-conditioned medium

A fraction of medium conditioned by embryonic mouse heart cells in culture promotes the growth of sympathetic and parasympathetic neurons in vitro. The factor stimulates neurite outgrowth, elevates specific activities of tyrosine hydroxylase and choline acetyltransferase in sympathetic ganglion explants, and enhances survival of dissociated sympathetic neurons in culture. The growth-promoting activity, which has a profound effect on survival of mouse sympathetic and parasympathetic neurons but little effect on mouse sensory neuron survival, is sensitive to trypsin and elevated temperature, suggesting association with a polypeptide or protein. Unlike nerve growth factor (NGF), the conditioned medium fraction is insensitive to anti-NGF antiserum, and fosters growth of mouse parasympathetic neurons. Consequently, the conditioned medium appears to contain a new nerve growth-promoting factor.     

Bioelectrical analysis of the regulatory interaction of sympathetic and parasympathetic nervous influences on the heart rhythm]

The changes of chronotropic effect on the isolated sinus node of the frog heart were studied during the separate and simultaneous stimulation of the sympathetic and intracardiac reflex parasympathetic pathways. Intracellular activity of the pacemaker cells was recorded. The separate stimulation of the intracardiac reflex system resulted in bradycardia (in winter) or tachycardia (in summer). Stimulation of sympathetic chain supervening the activation of the intracardiac pathways induced an intensification of both the parasympathetic bradycardia and tachycardia; these effects were cholinergic in nature. The recording of the intracellular pacemaker activity showed the existence of the complicated interaction between the sympathetic and parasympathetic pulse-mediator actions on the heart pacemaker both on the prepulase process and on the membrane polarization and other action potential parameters. Possible mechanisms of this interaction are discussed.     

Vasomotor axons of the lacrimal glands of monkeys and the ultrastructural identification of sympathetic terminals

Summary The ultrastructure of the perivascular axon terminals of the lacrimal gland in monkeys is investigated electronmicroscopically. Evidence is presented to show that axon terminals populated with small granular vesicles (300 to 500 Å) are sympathetic. Large granular vesicles (650 to 1,000 Å) are present in both sympathetic and parasympathetic terminals.Lacrimal arterioles have both sympathetic and parasympathetic axon terminals disposed between the adventitia and media, which do not form neuro-effector junctions. Capillaries and venules are sparsely innervated. Both parasympathetic and sympathetic axons are shown to innervate capillaries.Results from degeneration studies show that sympathetic and parasympathetic terminal axons lie within the cytoplasm of single Schwann cells.     

Nitric oxide synthase-containing neurons in rat parasympathetic, sympathetic and sensory ganglia: a comparative study

Summary In rats, the distribution of nerve structures staining for NADPH-diaphorase, and showing immunoreactivities for nitric oxide synthase (NOS), tyrosine hydroxylase and various neuropeptides was studied in sensory ganglia (dorsal root, nodose and trigeminal ganglia), in sympathetic ganglia (superior cervical, stellate, coeliac-superior and inferior mesenteric ganglia), parasympathetic ganglia (sphenopalatine, submandibular, sublingual and otic ganglia), and in the mixed parasympathetic/ sympathetic ganglia (major pelvic ganglia). The coincidence of neuronal cell bodies with strong NOS-immunoreactivity and strong NADPH diaphorase reactivity was almost total. The relative proportions of NOS-immunoreactive nerve cell bodies were largest in parasympathetic ganglia and major pelvic ganglia followed by sensory ganglia. In sympathetic ganglia no NOS-immunoreactive neuronal cell bodies could be detected. In parasympathetic and major pelvic ganglia, there was a very significant neuronal co-localization of immunoreactivities for NOS and vasoactive intestinal polypeptide (VIP). This was almost total in major pelvic ganglia, in which NOS-/VIP-immunoreactive nerve cell bodies were separate from sympathetic (tyrosine hydroxylase-/neuropeptide Y-immunoreactive), suggesting that NOS-/VIP-immuno-reactive neurons might also be parasympathetic.     

Glycoproteins of submaxillary saliva of the cat: differences in composition produced by sympathetic and parasympathetic nerve stimulation

Abstract— Saliva samples were obtained from the cannulated submaxillary ducts of the cat during stimulation of the peripheral cut end(s) of (1) the cervical sympathetic nerve, (2) the chordalingual (parasympathetic) nerve and (3) both nerves at the same time. In nine experiments the ratios of neuraminic acid to fucose and to hexosamine were consistently 2·5–4 times higher in saliva evoked by sympathetic nerve stimulation than in that produced by parasympathetic stimulation. This was not attributable to differences in the rate of synthesis of the carbohydrate of the glycoproteins or in salivary flow rate. The presence of glycolipids and blood glycoproteins was excluded. Saliva produced by stimulation of the sympathetic and parasympathetic nerves each showed a single, but different, peak after ultracentrifugation in 0·1 m -NaCl with 0·01 m -phosphate buffer (pH 7·4). The S_{20, w} of the former was 6·5 and of the latter, 39. Both peaks were demonstrable in saliva produced when both nerves were stimulated at the same time.     

Effect of electrical stimulation of the autonomic nerves on the levels and synthesis of cyclic nucleotides in the rat salivary glands: relationship to enhanced growth.

Electrical stimulation of either the parasympathetic or the sympathetic nerve supply to the parotid and submaxillary glands increases the intracellular level of cyclic GMP and the rate of DNA synthesis and cell division while only sympathetic stimulation raises cyclic AMP levels. The periods of electrical stimulation inducing hyperplasia also raise the cyclic GMP concentration but there is no similar correlation with changes in cyclic AMP levels. However, the extent of hyperplasia induced by parasympathetic and sympathetic stimulation is not directly related to the size of the increase in cyclic GMP concentration that these treatments produce. Changes in cyclic AMP levels are reflected in altered in vitro adenylate cyclase activity. This activity is raised after 2 min sympathetic stimulation and markedly decreased with 30 min sympathetic or parasympathetic stimulation. Guanylate cyclase activity shows no such changes with nerve stimulation.     

Autonomic nervous system activity in Macaca fascicularis

This study was performed to determine the contributions of the sympathetic and parasympathetic nervous systems to cardiovascular control. Hexamethonium was administered to block the autonomic ganglia, propranolol to block beta adrenergic receptors of the sympathetic nervous system, and methylatropine to block the parasympathetic nervous system. The results of this study indicate high sympathetic tone and low parasympathetic tone in resting Macaca fascicularis. These findings are different from those in man but are similar to other nonhuman primates.     

Treatment of a depressive disorder patient with EEG-driven photic stimulation

This study examined the effects of electroencephalographic-(EEG-) driven photic stimulation on a case of depressive disorder, as measured by a psychometric test of mood states, EEG parameters, and several autonomic indices. The EEG-driven photic stimulation enhances the alpha rhythm of brain waves using photic signals, the brightness of which is modulated by a subject's own alpha rhythm. The patient was a 37-year-old businessman, who was treated for depression with medication during the 13 months prior to his first visit to our hospital. He underwent two sets of inpatient treatment sessions, comprising first 16 and then 18 treatment sessions. The treatments brought about the following changes: an improvement in general mood state, alpha rhythm increase, cardiac parasympathetic suppression, and increased skin conductance level. In addition, significant correlations between alpha rhythm increase and cardiac parasympathetic suppression or cardiac sympathetic predominance were observed with each inpatient treatment. Significant correlations between alpha rhythm increase, cardiac parasympathetic suppression, or cardiac sympathetic predominance and the improvement of general mood state were also observed. Thus, from these observations, it was concluded that the alpha enhancement induced by EEG-driven photic stimulation produced an improvement in the patient's depressive symptomatology connected with cardiac parasympathetic suppression and sympathetic predominance.     

Effects of secretory nerve stimulation on acid phosphatase and peroxidase in submandibular saliva and acini in cats

Synopsis The effects of parasympathetic or sympathetic nerve stimulation either alone, or in combination, on the acid phosphatase-containing central acinar cells and the peroxidase-containing demilunar cells of the cat submandibular salivary gland have been investigated by histochemical and cytochemical techniques. The results obtained with these techniques were correlated with biochemical assays for both enzymes in the saliva secreted. The results indicate that, although both sets of nerves probably affect both sets of cells, the predominant secretory effect of parasympathetic stimulation is on the central cells and, conversely, the predominant secretory effect of sympathetic stimulation is on the demilunes. Sympathetic stimulation appeared also to have initiated synthesis of peroxidase in the demilunar cells, especially when it was superimposed upon parasympathetic stimulation.     

Torpor and ultradian rhythms require an intact signalling of the sympathetic nervous system

During entrance into torpor heart and respiration rates are greatly reduced in parallel with the reduction of metabolic rate, suggesting an involvement of parasympathetic control. We compared the effect of parasympathetic inhibition with the effect of sympathetic inhibition on spontaneous torpor behaviour in the Djungarian hamster. Hamsters were acclimated to short photoperiod and displayed their standard torpor pattern as observed from T_b records. Parasympathetic inhibition was achieved by a subcutaneous implant of 21-day release pellets with Atropine and the sympathetic noradrenergic pathway was inhibited with a single injection of 6-Hydroxydopamine. Atropine treatment did not affect the occurrence and quality of spontaneous daily torpor at all. However, the reversible sympathetic inhibition by 6-Hydroxydopamine injection resulted in a complete disappearance of torpor for about 6 days. These results conclude that the onset of daily torpor requires an intact noradrenergic signalling of the sympathetic nervous system. We further observed that parasympathetic as well as sympathetic blockade resulted in an immediate abolishment of ultradian rhythms of body temperature. This suggests that the expression of ultradian oscillations in body temperature require a continued interaction of sympathetic and parasympathetic activity.     

Salivation in the red kangaroo (Macropus rufus) during sympathetic nerve stimulation

1. Continuous electrical stimulation at low frequency (5 Hz) and short pulse duration (500 microseconds) of the cervical sympathetic trunk for periods up to 15 min caused no obvious flow from the parotid or mandibular glands of the red kangaroo. 2. Higher frequencies combined with longer pulse durations caused both glands to secrete. Flow reached maximum in less than 3 min and then declined but, on cessation of stimulation, flow increased again for a short period. This flow response may be caused by the interaction of the secretory response with myoepithelial contraction. 3. The parotid saliva had substantially higher protein, phosphate and hydrogen ion concentrations, and lower sodium concentrations than cholinergic parotid saliva. The low pH indicates bicarbonate concentrations far lower than in other sympathetic salivas. 4. The mandibular saliva had higher protein, urea and potassium, and lower chloride and hydrogen concentrations than cholinergic mandibular saliva.     

The relationship between nerves and smooth muscle cells in the rat iris

Summary The sphincter muscle in the rat iris forms irregular strands in the stroma. Bundles of unmyelinated axons run among the muscle cells. After sympathetic denervation some axons degenerate. This should indicate that sympathetic and parasympathetic nerves are present in the same nerve net. The parasympathetic axons possess varicosities, that is, enlargements containing mitochondria and synaptic vesicles. These varicosities show a similar structural relationship to the muscle cells as do the varicosities of sympathetic nerves. No obvious ultrastructural difference is observed between the sympathetic and parasympathetic varicosities.This study has been supported by research grants (U267 and Y247) from the Swedish Medical Research Council and by a Public Health Service Research Grant (NB05236-01) from the National Institute of Neurological Diseases and Blindness.