The effect of increased levels of endogenous nerve growth factor on mouse sympathetic ganglia

The present experiments showed that treatment of mice with a range of doses of testosterone propionate led to a significant increase in weight of the superior cervical ganglia (SCG). In all cases this was accompanied by an elevation of the level of nerve growth factor (NGF) in the submandibular glands (SMG) and, with the exception of animals treated with the lowest dose of testosterone, by an increase in weight of the SMG.Hypertrophy of the SCG was also found in mice treated with 5α-dihydrotestosterone which therefore excludes the possibility of the hypertrophy being due to a general metabolic effect of testosterone propionate.Treatment of mice with isoproterenol and of rats with testosterone propionate resulted in hypertrophy of the SMG but had no effect on the levels of NGF in the glands or on the weights of the SCG. These findings exclude the possibility that the hypertrophy of the SCG in testosterone-treated mice is a consequence of an increase in size of the SMG.It is concluded that the hypertrophy of the SCG in testosterone-treated mice results from the action of increased levels of endogenous NGF. The route of access of NGF responsible for the hypertrophy is discussed and a comparison is made of the effects produced by systemically administered NGF and increased levels of endogenous NGF.     

Nerve growth factor receptor immunoreactivity in the neuronal perikarya of human sensory and sympathetic nerve ganglia

We examined immunohistochemically the dorsal root ganglia, sympathetic ganglia, spinal cord, ventral and dorsal roots, and sciatic nerves obtained at autopsy from adult humans, using a monoclonal antibody against the human nerve growth factor receptor. We observed labelling in a granular pattern in the neuronal perikarya of dorsal root and sympathetic nerve ganglia. Ventral horn cells and axons were not labelled.     

Sex differences in nerve growth factor levels in superior cervical ganglia and pineals

The current studies were undertaken to determine whether males or neonatally testosterone-treated rats of either gender have elevated endogenous levels of NGF in the SCG and one of its targets, the pineal gland. The ages studied were 5 days postnatal, which is at the peak of normal neuron death in the SCG but before a significant gender difference is present; 15 days, when normal neuron death is largely complete and males have more SCG neurons than females; and 30 days, when target innervation has matured.

At 5 days, while neuron death is occurring, but before there is a significant gender difference in neuron number in the SCG, pineal glands and SCGs of males had higher NGF content than those of females. The increased NGF in the ganglia of males at the time that these neurons are undergoing neuron death may play a role in the development of the sex difference in SCG neuron numbers. At 15 days, females had more NGF in their pineal glands and SCGs than did males, even though males have significantly more SCG neurons at this age than do females. This gender difference in the developmental course of NGF content could promote the survival of different populations of neurons in males and females. By 30 days, SCG and pineal NGF content of males was almost twice that of females. This is consistent with the presence of more neurons in the SCGs of males at this age.

Both the pineal gland and the SCG showed a loss of approximately 80% content of NGF during the first postnatal month. In males, this loss occurred between postnatal days 5 and 15, while in females, the drop in NGF content occurred between postnatal days 15 and 30. Treatment with testosterone from birth reduced NGF content in the SCGs of both males and females at 5 days of age. The depression of NGF levels by testosterone treatment may reflect a further acceleration of the developmental fall of NGC levels.     

Effects of gonadal steroids on nerve growth factor receptors in sympathetic and sensory ganglia of neonatal rats

The numbers of neurons in the rat superior cervical sympathetic ganglion (SCG) differ in males and females, with the males having 30% more SCG neurons than females at 60 days of age. This sex difference arises during the early postnatal period, when testosterone administration increases the numbers of neurons and alters the nerve growth factor (NGF) content of the rat SCG. In contrast, there is no gender difference in number of neurons in the L1 dorsal root ganglion. In both males and females, the amount of NGF bound per ganglion increased between postnatal days 5 and 15 (P5 and P15) in both dorsal root ganglia (DRGs) and the SCG. There is also a gender difference in NGF binding: SCGs and DRGs of female rats at both P5 and P15 bind more NGF per ganglion than do those of males. This effect was more marked in DRGs than in the SCG. Treatment of neonatal females with testosterone reduced NGF binding in both SCGs and DRGs to levels comparable to males at P5, and in DRGs at P15. In contrast, treatment of males with testosterone from birth resulted in a 2-3 fold increase of NGF binding in both SCGs and DRGs as compared to controls at P15. At P15, testosterone treatment of females increased NGF binding in the SCG. Males and females had opposing responses to neonatal exposure to estradiol. Treatment with estradiol from birth increased NGF binding in SCGs and DRGs of females, but had no effect on NGF binding of SCGs, and reduced NGF binding in DRGs of males.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative studies on the effect of the nerve growth factor on sympathetic ganglia and adrenal medulla in newborn rats

The effect of nerve factor (NGF) and nerve growth factor antiserum (NGF-AS) on sympathetic ganglia and adrenal chromaffin cells of newborn rats was investigated in a comparative study.     

The alpha-bungarotoxin site and its relation to the cholinergic and nerve growth factor mediated increases in tyrosine hydroxylase activity in cultures of sympathetic ganglia and chromaffin cells

alpha-Bungarotoxin has been proposed to interact with a membrane site in neuronal tissue which has the characteristics of a nicotinic acetylcholine receptor and also a trophic receptor. A nerve cell function which is affected by both nicotinic stimulation and nerve growth factor is the induction of tyrosine hydroxylase. For this reason, alpha-bungarotoxin was tested on the carbachol-induced increase and nerve growth factor-mediated increase in tyrosine hydroxylase activity in two preparations of neuronal origin, organ cultures of rat superior cervical ganglia and cultured bovine adrenal medullary cells. The results demonstrate that the alpha-bungarotoxin site is not involved in tyrosine hydroxylase induction.     

Immunohistochemical phenotype of sensory neurons associated with sympathetic plexuses in the trigeminal ganglia of adult nerve growth factor transgenic mice

Following peripheral nerve injury, postganglionic sympathetic axons sprout into the affected sensory ganglia and form perineuronal sympathetic plexuses with somata of sensory neurons. This sympathosensory coupling contributes to the onset and persistence of injury-induced chronic pain. We have documented the presence of similar sympathetic plexuses in the trigeminal ganglia of adult mice that ectopically overexpress nerve growth factor (NGF), in the absence of nerve injury. In this study, we sought to further define the phenotype(s) of these trigeminal sensory neurons having sympathetic plexuses in our transgenic mice. Using quantitative immunofluorescence staining analyses, we show that the invading sympathetic axons specifically target sensory somata immunopositive for several biomarkers: NGF high-affinity receptor tyrosine kinase A (trkA), calcitonin gene-related peptide (CGRP), neurofilament heavy chain (NFH), and P2X purinoceptor 3 (P2X3). Based on these phenotypic characteristics, the majority of the sensory somata surrounded by sympathetic plexuses are likely to be NGF-responsive nociceptors (i.e., trkA expressing) that are peptidergic (i.e., CGRP expressing), myelinated (i.e., NFH expressing), and ATP sensitive (i.e., P2X3 expressing). Our data also show that very few sympathetic plexuses surround sensory somata expressing other nociceptive (pain) biomarkers, including substance P and acid-sensing ion channel 3. No sympathetic plexuses are associated with sensory somata that display isolectin B4 binding. Though the cellular mechanisms that trigger the formation of sympathetic plexus (with and without nerve injury) remain unknown, our new observations yield an unexpected specificity with which invading sympathetic axons appear to target a precise subtype of nociceptors. This selectivity likely contributes to pain development and maintenance associated with sympathosensory coupling.     

Mechanisms whereby nerve growth factor increases diacylglycerol levels in differentiating PC12 cells

We previously showed indirectly that the increase in diacylglycerol (DAG) levels caused by exposing differentiating PC12 cells to nerve growth factor (NGF) must derive mainly from de novo synthesis and, to a lesser and transient extent, from the hydrolysis of [3H]phosphatidylinositol (PI). To explore further the biochemical mechanisms of this increase, we measured, in PC12 cells, DAG synthesis from glycerol or various fatty acids; its liberation from phosphatidylcholine (PC); and the activities of various enzymes involved in DAG production and metabolism. Among cells exposed to NGF (0-116 h), the labeling of DAG from [3H]glycerol peaked earlier than that of [3H]PC, and the specific radioactivity of [3H]glycerol-labeled DAG was much higher than those of the [3H]phospholipids, indicating that [3H]DAG synthesis precedes [3H]phospholipid synthesis. NGF treatment also increased (by 50-330%) the incorporation of monounsaturated ([3H]oleic acid) and polyunsaturated ([14C]linoleic acid or [3H]arachidonic acid) fatty acids into DAG, and, by 15-70%, into PC. NGF treatment increased the activities of long chain acyl-CoA synthetases (LCASs), including oleoyl-CoA synthetase and arachidonoyl-CoA synthetase, by 150-580% over control, but cholinephosphotransferase activity rose by only 60%, suggesting that the synthesis of DAG in the cells was increased to a greater extent than its utilization. NGF did not promote the breakdown of newly formed [3H]PC to [3H]DAG, nor did it consistently affect the activities of phospholipase C or D. NGF did increase phospholipase A2 activity, however the hydrolysis catalyzed by this enzyme does not liberate DAG. Hence the major source of the increased DAG levels in PC12 cells exposed to NGF appears to be enhanced de novo DAG synthesis, probably initiated by the activation of LCASs, rather than the breakdown of PC or PI.     

Retrogradely transported nerve growth factor increases ornithine decar☐ylase activity in rat superior cervical ganglia

Nerve growth factor (NGF) transported intraaxonally from the adrenergic nerve terminals in the iris to the cell bodies in the superior cervical ganglion resulted in an increase in the activity of the enzyme ornithine decarboxylase in the ganglion. This occurred in both six-day-old and adult rats with the relative effect of the retrogradely transported NGF being greater in adult animals. These results suggest that the induction of ornithine decarboxylase by NGF may be due to the stimulation of intracellular receptors.     

The α-bungarotoxin site and its relation to the cholinergic and nerve growth factor mediated increases in tyrosine hydroxylase activity in cultures of sympathetic ganglia and chromaffin cells

α-Bungarotoxin has been proposed to interact with a membrane site in neuronal tissue which has the characteristics of a nicotinic acetylcholine receptor and also a trophic receptor. A nerve cell function which is affected by both nicotinic stimulation and nerve growth factor is the induction of tyrosine hydroxylase. For this reason, α-bungarotoxin was tested on the carbachol-induced increase and nerve growth factor-mediated increase in tyrosine hydroxylase activity in two preparations of neuronal origin, organ cultures of rat superior cervical ganglia and cultured bovine adrenal medullary cells. The results demonstrate that the α-bungarotoxin site is not involved in tyrosine hydroxylase induction.     

An acceleration of age-related increases in levels of the β-subunit of nerve growth factor in selected tissues from senescence-accelerated mice (SAM-P/8)

An investigation was made of age-related changes in levels of the β-subunit of nerve growth factor (β-NGF) in selected tissues and of testosterone in serum in senescence-accelerated mice (SAM-P/8) and in the control mice (senesence-resistant mice; SAM-R/1). The concentrations of testosterone in serum were higher in SAM-P/8 than in SAM-R/1 at ages 2 and 4 mo. The level of β-NGF in the thymus from SAM-R/1 increased with age, resulting in a statistically significant difference in its level between mice at ages 2 and 12 mo. By contrast, there was a transient increase in SAM-P/8 at around age 4 mo with a subsequent decrease. Consequently, significant differences were apparent in levels of β-NGF between the two types of mouse at ages 2 and 4 mo. Similar results were obtained in the adrenal gland and testis. Compared to SAM-R/1 at age 2 mo, the average concentrations of β-NGF in the hypophysis were higher in SAM-R/1 at ages 4 and 8 mo and in SAM-P/8 at all ages. In other tissues tested, no remarkable differences were detected. Our present results indicate that, in SAM-P/8, the elevation in levels of β-NGF in the thymus, adrenal gland, testis, and hypophysis occurs in the early period of life compared to the control mice. Possible dysfunction of the disorder of hypophysis is discussed.     

Muscarinic receptor binding and oxidative enzyme activities in the adult rat superior cervical ganglion: effects of 6-hydroxydopamine and nerve growth factor

Administration of 6-hydroxydopamine to adult rats results in changes in the superior cervical ganglion similar to those noted after axotomy; namely, a decrease in muscarinic receptor binding and increases in activities of the oxidative enzymes of the pentose phosphate pathway. These changes were either prevented or attenuated markedly by the systemic administration of nerve growth factor. Administration of nerve growth factor alone did not significantly increase N-methylscopolamine binding in the ganglion or reduce the activities of the oxidative enzymes. Explants of the ganglion maintained in serum-free medium over a period of 3 days demonstrated increases in oxidative enzyme activity and a decrease in N-methylscopolamine binding. Addition of 20 nM nerve growth factor to the culture medium prevented the decline in N-methylscopolamine binding in ganglion explants. The increases in oxidative enzyme activities were unaltered. Addition of high amounts of nerve growth factor, 200 nM, resulted in a significant increase in tyrosine hydroxylase activity but no further increase in N-methylscopolamine binding in ganglion explants. Glucocorticoids added to the culture medium did not affect the muscarinic binding or enzyme activities. Thus, decreases in muscarinic binding activity which occur in the superior cervical ganglion after axotomy or 6-hydroxydopamine treatment may be explained by a loss of nerve growth factor supplied to the ganglion. Increases in the oxidative enzymes of the pentose phosphate pathway that occur in the ganglion after axonal injury appear to involve additional factors.     

Characteristics of the association of nerve growth factor with primary cultures of rat sympathetic neurons

Long-term primary cultures of rat sympathetic neurons require NGF for survival and development. The kinetics of the interaction of 125I-NGF with sympathetic neuron cultures suggests the presence of diffusional barriers preventing a determination of true dissociation and association rate constants. Although the observed rate constants do not accurately reflect the microscopic interaction of NGF with receptor, the ratio of the observed rate constants does provide a good estimate of the KD. This value (1 X 10(-9)M) agrees with earlier steady state measurements of the KD. The association of 125I-NGF with neuronal cultures is temperature-dependent with internalization and retrograde transport occurring at 37 degrees C. The retrograde transport of 125I-NGF in compartmentalized neuronal cultures is concentration dependent and saturates at about 100 ng/ml (4 X 10(-9)M). The amount of 125I-NGF accumulated by retrograde transport appears to be increased subsequent to a period of NGF-starvation. The increase in uptake does not appear to be due to an increase in NGF receptor number since the number of binding sites is not greatly increased upon NGF starvation.     

Increased CSF levels of nerve growth factor in patients with Alzheimer's disease

The authors quantitated CSF levels of nerve growth factor (NGF) in patients with AD, nondemented control subjects (CTR), and age-matched patients with major depression (DE). CSF levels of NGF were markedly higher in the AD group than in both the CTR and DE groups (p < 0.01 and p < 0.001). Increased CSF levels of NGF in AD patients may reflect reported accumulation of NGF in the AD brain and may constitute a candidate marker for clinical diagnosis and therapeutic monitoring.