Repeated Intravenous Administration of Human Neural Stem Cells Producing Choline Acetyltransferase Exerts Anti-Aging Effects in Male F344 Rats.

Major features of aging might be progressive decreases in cognitive function and physical activity, in addition to withered appearance. Previously, we reported that the intracerebroventricular injection of human neural stem cells (NSCs named F3) encoded the choline acetyltransferase gene (F3.ChAT). The cells secreted acetylcholine and growth factors (GFs) and neurotrophic factors (NFs), thereby improving learning and memory function as well as the physical activity of aged animals. In this study, F344 rats (10 months old) were intravenously transplanted with F3 or F3.ChAT NSCs (1 × 106 cells) once a month to the 21st month of age. Their physical activity and cognitive function were investigated, and brain acetylcholine (ACh) and cholinergic and dopaminergic system markers were analyzed. Neuroprotective and neuroregenerative activities of stem cells were also confirmed by analyzing oxidative damages, neuronal skeletal protein, angiogenesis, brain and muscle weights, and proliferating host stem cells. Stem cells markedly improved both cognitive and physical functions, in parallel with the elevation in ACh levels in cerebrospinal fluid and muscles, in which F3.ChAT cells were more effective than F3 parental cells. Stem cell transplantation downregulated CCL11 and recovered GFs and NFs in the brain, leading to restoration of microtubule-associated protein 2 as well as functional markers of cholinergic and dopaminergic systems, along with neovascularization. Stem cells also restored muscular GFs and NFs, resulting in increased angiogenesis and muscle mass. In addition, stem cells enhanced antioxidative capacity, attenuating oxidative damage to the brain and muscles. The results indicate that NSCs encoding ChAT improve cognitive function and physical activity of aging animals by protecting and recovering functions of multiple organs, including cholinergic and dopaminergic systems, as well as muscles from oxidative injuries through secretion of ACh and GFs/NFs, increased antioxidant elements, and enhanced blood flow.

CDNF rescues motor neurons in models of amyotrophic lateral sclerosis by targeting endoplasmic reticulum stress.

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects motor neurons in the spinal cord, brainstem and motor cortex, leading to paralysis and eventually to death within 3-5 years of symptom onset. To date, no cure or effective therapy is available. The role of chronic endoplasmic reticulum stress in the pathophysiology of amyotrophic lateral sclerosis, as well as a potential drug target, has received increasing attention. Here, we investigated the mode of action and therapeutic effect of the endoplasmic reticulum-resident protein cerebral dopamine neurotrophic factor in three preclinical models of amyotrophic lateral sclerosis, exhibiting different disease development and aetiology: (i) the conditional choline acetyltransferase-tTA/TRE-hTDP43-M337V rat model previously described; (ii) the widely used SOD1-G93A mouse model; and (iii) a novel slow-progressive TDP43-M337V mouse model. To specifically analyse the endoplasmic reticulum stress response in motor neurons, we used three main methods: (i) primary cultures of motor neurons derived from embryonic Day 13 embryos; (ii) immunohistochemical analyses of spinal cord sections with choline acetyltransferase as spinal motor neuron marker; and (iii) quantitative polymerase chain reaction analyses of lumbar motor neurons isolated via laser microdissection. We show that intracerebroventricular administration of cerebral dopamine neurotrophic factor significantly halts the progression of the disease and improves motor behaviour in TDP43-M337V and SOD1-G93A rodent models of amyotrophic lateral sclerosis. Cerebral dopamine neurotrophic factor rescues motor neurons in vitro and in vivo from endoplasmic reticulum stress-associated cell death and its beneficial effect is independent of genetic disease aetiology. Notably, cerebral dopamine neurotrophic factor regulates the unfolded protein response initiated by transducers IRE1α, PERK and ATF6, thereby enhancing motor neuron survival. Thus, cerebral dopamine neurotrophic factor holds great promise for the design of new rational treatments for amyotrophic lateral sclerosis.

Therapeutic effects of KCC2 chloride transporter activation on detrusor overactivity in mice with spinal cord injury.

This study aimed to clarify whether downregulation of K+-Cl- cotransporter 2 (KCC2) in the sacral parasympathetic nucleus (SPN) of the lumbosacral spinal cord, from which the efferent pathway innervating the bladder originates, causes cellular hyperexcitability and triggers detrusor overactivity (DO) in spinal cord injury (SCI). SCI was produced by Th8-9 spinal cord transection in female C57BL/6 mice. At 4 wk after SCI, CLP290, a KCC2 activator, was administered, and cystometry was performed. Thereafter, neuronal activity with c-fos staining and KCC2 expression in cholinergic preganglionic parasympathetic neurons in the SPN was examined using immunohistochemistry. Firing properties of neurons in the SPN region were evaluated by extracellular recordings in the spinal cord slice preparations. DO evident as nonvoiding contractions was significantly reduced by CLP290 treatment in SCI mice. The number of c-fos-positive cells and coexpression of c-fos in choline acetyltransferase-positive cells were decreased in the SPN region of the SCI CLP290-treated group versus the SCI vehicle-treated group. KCC2 immunoreactivity was present on the cell membrane of SPN neurons and normalized fluorescence intensity of KCC2 in choline acetyltransferase-positive SPN neurons was decreased in the SCI vehicle-treated group versus the spinal intact vehicle-treated group but recovered in the SCI CLP290-treated group. Extracellular recordings showed that CLP290 suppressed the high-frequency firing activity of SPN neurons in SCI mice. These results indicated that SCI-induced DO is associated with downregulation of KCC2 in preganglionic parasympathetic neurons and that activation of KCC2 transporters can reduce DO, increase KCC2 expression in preganglionic parasympathetic neurons, and decrease neuronal firing of SPN neurons in SCI mice.NEW & NOTEWORTHY This study is the first report to suggest that activation of the Cl- transporter K+-Cl- cotransporter 2 may be a therapeutic modality for the treatment of spinal cord injury-induced detrusor overactivity by targeting bladder efferent pathways.

Targeting acetylcholine signaling modulates persistent drug tolerance in EGFR-mutant lung cancer and impedes tumor relapse.

Although first-line epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy is effective for treating EGFR-mutant non-small cell lung cancer (NSCLC), it is now understood that drug-tolerant persister (DTP) cells escaping from initial treatment eventually drives drug resistance. Here, through integration of metabolomics and transcriptomics, we found that the neurotransmitter acetylcholine (ACh) was specifically accumulated in DTP cells, and demonstrated that treatment with EGFR-TKI heightened the expression of the rate-limiting enzyme choline acetyltransferase (ChAT) in ACh biosynthesis via YAP mediation. Genetic and pharmacological manipulation of ACh biosynthesis or ACh signaling could predictably regulate the extent of DTP formation in vitro and in vivo. Strikingly, pharmacologically targeting ACh/M3R signaling with an FDA-approved drug, darifenacin, retarded tumor relapse in vivo. Mechanistically, upregulated ACh metabolism mediated drug tolerance in part through activating WNT signaling via ACh muscarinic receptor 3 (M3R). Importantly, we showed that aberrant ACh metabolism in patients with NSCLC played a potential role in predicting EGFR-TKI response rate and progression-free survival. Our study therefore defines a therapeutic strategy - targeting the ACh/M3R/WNT axis - for manipulating EGFR TKI drug tolerance in the treatment of NSCLC.

The Aqueous Extract of Humulus japonicus Ameliorates Cognitive Dysfunction in Alzheimer's Disease Models via Modulating the Cholinergic System.

Humulus japonicus (HJ) is an herbal medicine, which has been reported as being antioxidative and anti-inflammatory. The present study aimed to investigate the effect of oral administration of HJ water extract (HJW) on cognitive function through the cholinergic system in Alzheimer's disease (AD) mouse models. Institute of Cancer Research mice injected with beta-amyloid (Aß) (1-42) (i.c.v.) and APP/PS1 transgenic (TG) mice were orally administered with HJW at 500 mg/kg/day for 3 weeks. Aß-injected mice and APP/PS1 TG mice showed cognitive dysfunction, which was evaluated by various behavioral tests. HJW treatment significantly attenuated memory impairments in Aß-injected mice and APP/PS1 TG mice. Aß injection decreased acetylcholine (ACh) concentrations and choline acetyltransferase (ChAT) activity, and increased acetylcholinesterase (AChE) activity. These cholinergic impairments were also found in APP/PS1 TG mice. HJW significantly attenuated cholinergic alterations in Aß-injected mice and TG mice. In addition, HJW significantly decreased Aß plaque deposition in the cerebral cortex and hippocampus of TG mice. Therefore, the present study demonstrated that HJW protected against AD-related memory impairments via enhancing the cholinergic system and inhibiting Aß plaque deposition.

Korean Red Pine (Pinus densiflora) Bark Extract Attenuates Aß-Induced Cognitive Impairment by Regulating Cholinergic Dysfunction and Neuroinflammation.

In this study, we investigated the anti-amnesic effect of Korean red pine (Pinus densiflora) bark extract (KRPBE) against amyloid beta1-42 (Aß1-42)-induced neurotoxicity. We found that treatment with KRPBE improved the behavioral function in Aß-induced mice, and also boosted the antioxidant system in mice by decreasing malondialdehyde (MDA) content, increasing superoxide dismutase (SOD) activities, and reducing glutathione (GSH) levels. In addition, KRPBE improved the cholinergic system by suppressing reduced acetylcholine (ACh) content while also activating acetylcholinesterase (AChE), regulating the expression of choline acetyltransferase (ChAT), postsynaptic density protein-95 (PSD-95), and synaptophysin. KRPBE also showed an ameliorating effect on cerebral mitochondrial deficit by regulating reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and ATP levels. Moreover, KRPBE modulated the expression levels of neurotoxicity indicators Aß and phosphorylated tau (p-tau) and inflammatory cytokines TNF-α, p-IκB-α, and IL-1ß. Furthermore, we found that KRPBE improved the expression levels of neuronal apoptosis-related markers BAX and BCl-2 and increased the expression levels of BDNF and p-CREB. Therefore, this study suggests that KRPBE treatment has an anti-amnestic effect by modulating cholinergic system dysfunction and neuroinflammation in Aß1-42-induced cognitive impairment in mice.

Study of lead-induced neurotoxicity in cholinergic cells differentiated from bone marrow-derived mesenchymal stem cells.

The developing brain is susceptible to the neurotoxic effects of lead. Exposure to lead has main effects on the cholinergic system and causes reduction of cholinergic neuron function during brain development. Disruption of the cholinergic system by chemicals, which play important roles during brain development, causes of neurodevelopmental toxicity. Differentiation of stem cells to neural cells is recently considered a promising tool for neurodevelopmental toxicity studies. This study evaluated the toxicity of lead acetate exposure during the differentiation of bone marrow-derived mesenchyme stem cells (bone marrow stem cells, BMSCs) to CCholinergic neurons. Following institutional animal care review board approval, BMSCs were obtained from adult rats. The differentiating protocol included two stages that were pre-induction with ß-mercaptoethanol (BME) for 24 h and differentiation to cholinergic neurons with nerve growth factor (NGF) over 5 days. The cells were exposed to different lead acetate concentrations (0.1-100 µm) during three stages, including undifferentiated, pre-induction, and neuronal differentiation stages; cell viability was measured by MTT assay. Lead exposure (0.01-100 µg/ml) had no cytotoxic effect on BMSCs but could significantly reduce cell viability at 50 and 100 µm concentrations during pre-induction and neuronal differentiation stages. MAP2 and choline acetyltransferase (ChAT) protein expression were investigated by immunocytochemistry. Although cells treated with 100 µm lead concentration expressed MAP2 protein in the differentiation stages, they had no neuronal cell morphology. The ChAT expression was negative in cells treated with lead. The present study showed that differentiated neuronal BMSCs are sensitive to lead toxicity during differentiation, and it is suggested that these cells be used to study neurodevelopmental toxicity.

Effect of sevoflurane preconditioning on sleep reintegration after alteration by lipopolysaccharide.

Despite extensive evidence on the organ protective effects of sevoflurane, its effect on disturbed sleep remains unclear. We hypothesised that sevoflurane preconditioning positively impacts disturbed sleep caused by systemic inflammation. A prospective, randomised laboratory investigation was conducted in C57BL/6J mice. A mouse model of lipopolysaccharide (LPS)-induced systemic inflammation was employed to investigate the effects of sevoflurane on sleep recovery. Symptom recovery was evaluated through electroencephalography/electromyography (EEG/EMG) and histological studies. The mice were exposed to 2% sevoflurane before and after peritoneal injection of LPS. The EEG and EMG were recorded for 24 h after the procedure. Brain tissue was harvested after the sevoflurane/LPS procedure and was immunostained using individual antibodies against choline acetyltransferase (ChAT) and Fos. The ChAT-positive and ChAT/Fos double-positive cells were analysed quantitatively in the pedunculopontine tegmental nucleus and laterodorsal tegmental nucleus (PPTg/LDTg). Compared with control mice, mice preconditioned with sevoflurane but not post-conditioned showed a significant increase in rapid eye movement (REM) sleep during EEG recording following the LPS challenge. They also demonstrated a shorter REM latency, indicating an early recovery from LPS-altered sleep. The bouts of REM episodes were retained with sevoflurane preconditioning. More ChAT/Fos double-positive cells were observed in the PPTg/LDTg in the sevoflurane preconditioning plus LPS group than in the LPS-only group. Sevoflurane preconditioning promotes recovery from altered sleep induced by systemic inflammation. Activation of PPTg/LDTg is considered a mechanism underlying sleep reintegration. The recovery phenomenon shows potential for clinical application in cases of sleep disturbances induced by systemic inflammation.

Hippocampal acetylcholine modulates stress-related behaviors independent of specific cholinergic inputs.

Acetylcholine (ACh) levels are elevated in actively depressed subjects. Conversely, antagonism of either nicotinic or muscarinic ACh receptors can have antidepressant effects in humans and decrease stress-relevant behaviors in rodents. Consistent with a role for ACh in mediating maladaptive responses to stress, brain ACh levels increase in response to stressful challenges, whereas systemically blocking acetylcholinesterase (AChE, the primary ACh degradative enzyme) elicits depression-like symptoms in human subjects, and selectively blocking AChE in the hippocampus increases relevant behaviors in rodents. We used an ACh sensor to characterize stress-evoked ACh release, then used chemogenetic, optogenetic and pharmacological approaches to determine whether cholinergic inputs from the medial septum/diagonal bands of Broca (MSDBB) or ChAT-positive neurons intrinsic to the hippocampus mediate stress-relevant behaviors in mice. Chemogenetic inhibition or activation of MSDBB cholinergic neurons did not result in significant behavioral effects, while inhibition attenuated the behavioral effects of physostigmine. In contrast, optogenetic stimulation of septohippocampal terminals or selective chemogenetic activation of ChAT-positive inputs to hippocampus increased stress-related behaviors. Finally, stimulation of sparse ChAT-positive hippocampal neurons increased stress-related behaviors in one ChAT-Cre line, which were attenuated by local infusion of cholinergic antagonists. These studies suggest that ACh signaling results in maladaptive behavioral responses to stress if the balance of signaling is shifted toward increased hippocampal engagement.

Systemic administration of choline acetyltransferase decreases blood pressure in murine hypertension.

Acetylcholine (ACh) decreases blood pressure by stimulating endothelium nitric oxide-dependent vasodilation in resistance arterioles. Normal plasma contains choline acetyltransferase (ChAT) and its biosynthetic product ACh at appreciable concentrations to potentially act upon the endothelium to affect blood pressure. Recently we discovered a T-cell subset expressing ChAT (TChAT), whereby genetic ablation of ChAT in these cells produces hypertension, indicating that production of ACh by TChAT regulates blood pressure. Accordingly, we reasoned that increasing systemic ChAT concentrations might induce vasodilation and reduce blood pressure. To evaluate this possibility, recombinant ChAT was administered intraperitoneally to mice having angiotensin II-induced hypertension. This intervention significantly and dose-dependently decreased mean arterial pressure. ChAT-mediated attenuation of blood pressure was reversed by administration of the nitric oxide synthesis blocker L-nitro arginine methyl ester, indicating ChAT administration decreases blood pressure by stimulating nitic oxide dependent vasodilation, consistent with an effect of ACh on the endothelium. To prolong the half life of circulating ChAT, the molecule was modified by covalently attaching repeating units of polyethylene glycol (PEG), resulting in enzymatically active PEG-ChAT. Administration of PEG-ChAT to hypertensive mice decreased mean arterial pressure with a longer response duration when compared to ChAT. Together these findings suggest further studies are warranted on the role of ChAT in hypertension.

Effect of natural products on diabetes associated neurological disorders.

Diabetes mellitus, a metabolic disorder, is associated with neurological complications such as depression, anxiety, hypolocomotion, cognitive dysfunction, phobias, anorexia, stroke, pain, etc. Traditional system of medicine is long known for its efficient management of diabetes. The current review discusses the scope of some common medicinal herbs as well as secondary metabolites with a special focus on diabetes-mediated central nervous system complications. Literatures suggest that natural products reduce diabetes-mediated neurological complications partly by reducing oxidative stress and/or inflammation or apoptosis in certain brain regions. Natural products are known to modulate diabetes-mediated alterations in the level of acetylcholinesterase, choline acetyltransferase, monoamine oxidase, serotonin receptors, muscarinic receptors, insulin receptor, nerve growth factor, brain-derived neurotrophic factor, and neuropeptide in brain. Further, there are several natural products reported to manage diabetic complications with unknown mechanism. In conclusion, medicinal plants or their secondary metabolites have a wide scope and possess therapeutic potential to effectively manage neurological complications associated with chronic diabetes.

Cholinergic depletion in the nucleus accumbens: effects on amphetamine response and sensorimotor gating.

A delicate balance between dopaminergic and cholinergic activity in the ventral striatum or nucleus accumbens (N.Acc) appears to be important for optimal performance of a wide range of behaviours. While functional interactions between these systems are complex, some data suggest that acetylcholine in the N.Acc. may dampen the effects of excessive dopamine (DA) release. We proposed that a reduction in the density of cholinergic interneurons in the N.Acc would result in behavioural alterations suggestive of a hyper-responsiveness of the N.Acc DA system. The present study aimed to produce a sustainable depletion of cholinergic neurons in the N.Acc in the rat and study the effects of such lesions on DA-dependent behaviour. A novel saporin immunotoxin targeting choline acetyltransferase was microinjected bilaterally into the N.Acc of adult rats. We confirmed histologically that two weeks post-injection, animals show a local, selective depletion of cholinergic interneurons (mean cell loss of 44%). Cholinergic-depleted rats showed a marked increase in the locomotor activating effects of amphetamine. In addition, such lesions induced a disruption of sensorimotor gating processes, reflected in a reduction in the prepulse inhibition of the acoustic startle response, which was reversed by haloperidol. These data are suggestive of pronounced hyper-responsiveness of the meso-accumbens DA system which may be of relevance to the pathophysiology of schizophrenia, a condition where selective reduction in the number of ventral striatal cholinergic neurons has been demonstrated.

Complementary remedy of aged-related learning and memory deficits via exogenous choline acetyltransferase.

The present study aimed to examine whether the aged mice with naturally occurring cognitive deficits in learning and memory would benefit from supplementation of choline acetyltransferase (ChAT), the biosynthetic enzyme for neurotransmitter acetylcholine. Delivered by protein transduction domain (PTD), ChAT could pass through the blood-brain barrier, enter the neurons, interact with heat shock protein 70kDa, and retain enzyme activity. In behavior tests, PTD-ChAT given to the aged and memory-deficient mice almost completely reversed the behavioral changes, such as impairment of memory retention in the step-through test (an index of long-term memory) and prolonged swimming time in water maze test (an index of spatial recognition memory). The results suggest a novel and potential therapeutic use of PTD-ChAT in the age-related cognitive deficits.

Fetal chlorpyrifos exposure: adverse effects on brain cell development and cholinergic biomarkers emerge postnatally and continue into adolescence and adulthood.

Fetal and childhood exposures to widely used organophosphate pesticides, especially chlorpyrifos (CPF), have raised concerns about developmental neurotoxicity. Previously, biomarkers for brain cell number, cell packing density, and cell size indicated that neonatal rats were more sensitive to CPF than were fetal rats, yet animals exposed prenatally still developed behavioral deficits in adolescence and adulthood. In the present study, we administered CPF to pregnant rats on gestational days 17-20, using regimens devoid of overt fetal toxicity. We then examined subsequent development of acetylcholine systems in forebrain regions involved in cognitive function and compared the effects with those on general biomarkers of cell development. Choline acetyltransferase, a constitutive marker for cholinergic nerve terminals, showed only minor CPF-induced changes during the period of rapid synaptogenesis. In contrast, hemicholinium-3 binding to the presynaptic choline transporter, which is responsive to nerve impulse activity, displayed marked suppression in the animals exposed to CPF; despite a return to nearly normal values by weaning, deficits were again apparent in adolescence and adulthood. There was no compensatory up-regulation of cholinergic receptors, as m2-muscarinic cholinergic receptor binding was unchanged. CPF also elicited delayed-onset alterations in biomarkers for general aspects of cell integrity, with reductions in cell packing density, increases in relative cell size, and contraction of neuritic extensions; however, neither the magnitude nor timing of these changes was predictive of the cholinergic defects. The present findings indicate a wide window of vulnerability of cholinergic systems to CPF, extending from prenatal through postnatal periods, occurring independently of adverse effects on general cellular neurotoxicity.

Developmental neurotoxicity of chlorpyrifos: what is the vulnerable period?

Previously, we found that exposure of neonatal rats to chlorpyrifos (CPF) produced brain cell damage and loss, with resultant abnormalities of synaptic development. We used the same biomarkers to examine prenatal CPF treatment so as to define the critical period of vulnerability. One group of pregnant rats received CPF (subcutaneous injections in dimethyl sulfoxide vehicle) on gestational days (GD) 17-20, a peak period of neurogenesis; a second group was treated on GD9-12, the period of neural tube formation. In the GD17-20 group, the threshold for a reduction in maternal weight gain was 5 mg/kg/day; at or below that dose, there was no evidence (GD21) of general fetotoxicity as assessed by the number of fetuses or fetal body and tissue weights. Above the threshold, there was brain sparing (reduced body weight with an increase in brain/body weight ratio) and a targeting of the liver (reduced liver/body weight). Indices of cell packing density (DNA per gram of tissue) and cell number (DNA content) similarly showed effects only on the liver; however, there were significant changes in the protein/DNA ratio, an index of cell size, in fetal brain regions at doses as low as 1 mg/kg, below the threshold for inhibition of fetal brain cholinesterase (2 mg/kg). Indices of cholinergic synaptic development showed significant CPF-induced defects but only at doses above the threshold for cholinesterase inhibition. With earlier CPF treatment (GD9-12), there was no evidence of general fetotoxicity or alterations of brain cell development at doses up to the threshold for maternal toxicity (5 mg/kg), assessed on GD17 and GD21; however, augmentation of cholinergic synaptic markers was detected at doses as low as 1 mg/kg. Compared with previous work on postnatal CPF exposure, the effects seen here required doses closer to the threshold for fetal weight loss; this implies a lower vulnerability in the fetal compared with the neonatal brain. Although delayed neurotoxic effects of prenatal CPF may emerge subsequently in development, our results are consistent with the preferential targeting of late developmental events such as gliogenesis, axonogenesis, and synaptogenesis.

Cholinergic deficits in aged rat spinal cord: restoration by GM1 ganglioside.

Cholinergic neurons of spinal cord are central for the processing of motor, autonomic, and sensory modalities. Aging is associated with a variety of motor and autonomic symptoms that might be attributed, in part, to impaired spinal cord function. We found that cholinergic neurochemistry is diminished in the spinal cord of 22-24-month-old rats compared with 3-month-old rats. Choline acetyltransferase, high-affinity choline transport and hemicholinium-3 binding to the choline carrier were reduced in the aged spinal cord. The activity of the choline transporter and the hemicholinium-3 binding were decreased in all spinal segments, cervical, thoracic, lumbar and sacral. Hemicholinium-3 binding was reduced in ventral and dorsal horns along all spinal segments. The activity of choline acetyltransferase was decreased only in cervical and lumbar cord. Treatment of aged animals with GM1 induced the recovery of the presynaptic cholinergic markers in the aged spinal cord.

Acetylcholine and vasoactive intestinal peptide in cerebral blood vessels: effect of extirpation of the sphenopalatine ganglion.

The innervation of cerebral blood vessels by nerve fibers containing acetylcholinesterase (AChE) and vasoactive intestinal peptide (VIP) and the vasomotor effects of the two neurotransmitters have been analyzed in the rat following the uni- or bilateral removal of the sphenopalatine ganglion (SPG), which is thought to be the major origin of this innervation. Histochemistry of AChE-positive nerve fibers and the immunoreactivity toward VIP revealed only a 30% reduction in the innervation pattern of the rostral part of the cerebral circulation following the operation. At approximately 4 weeks postoperatively, the original nerve network was restored. Quantitative measurements of cholineacetyltransferase activity and VIP revealed similar reductions in the levels of collected large cerebral arteries at the base of the brain and in small pial vessels overlying the cerebral cortex at the various postoperative times following uni- or bilateral removal of the SPG. The two techniques thus complemented each other. Vasomotor reactivity to acetylcholine (ACh) and VIP was examined in proximal segments of the middle cerebral artery at the various postoperative times. Generally, the removal of the SPG had no effect on the responses to ACh or VIP. The evidence indicates that only approximately one-third of the cholinergic/VIP innervation of the rostral part of the cerebral circulation originates in the SPG.

[Determination of cholinesterase activity in Fasciola hepatica homogenates]. / Determinación de actividad colinesterásica en homogeneizados de Fasciola hepatica.

The cholinesterase activity in Fasciola hepatica homogenates was studied through biological techniques. Results depict that the contractile stimulating action of a constant acetylcholine dose on the isolated rat duodenum is withdrawn when the agent is previously incubated at 37 degrees C during 30 minutes with different dilutions (20%, 40% and 80%) of Fasciola hepatica homogenates. The action is recovered when an anticholinesterase, as neostigmine is previously added to the homogenate. Since these effects are similar to those obtained when different dilutions of human blood serum with a high content of cholinesterase are led to act upon the acetylcholine dose, it is concluded that the acetylcholine inactivation induced by Fasciola hepatica homogenates results from the existence of such enzyme within this parasite.