Acrylamide Intoxication Research Articles

Changes in sympathetic and endothelium-mediated responses in the rabbit central ear artery after acrylamide treatment

The effect of acrylamide intoxication on the innervation and local control of the rabbit central ear artery was investigated. There was no difference in the noradrenaline, neuropeptide Y and calcitonin gene-related peptide tissue content between control and experimental animals. There was, however, a slight reduction in catecholamine histofluorescence. Although the contractile efficiency of the rabbit central ear artery as measured by responses to potassium chloride was unchanged, nerve-mediated contractile responses were significantly attenuated in acrylamide-treated animals. Contractile responses induced by exogenous α,β-methylene ATP were markedly increased after acrylamide treatment, in contrast to contractions induced by exogenous noradrenaline which were attenuated at maximal concentrations. Modulatory effects of nerve-mediated contractile responses by neuropeptide Y were unaffected by acrylamide intoxication. It therefore appears that acrylamide intoxication damages sympathetic cotransmission, perhaps with preferential action on the purinergic component. Endothelium-dependent relaxant responses to acetylcholine and substance P were attenuated in acrylamide-treated animals, whereas relaxant responses mediated by calcitonin gene-related peptide (endothelium independent) were unaffected. The question of whether the damage to the endothelial cell action is a primary effect, or a secondary consequence of sympathetic nerve damage, is discussed.

Acrylamide-induced visceral neuropathy: Evidence for the involvement of capsaicin-sensitive nerves of the rat urinary bladder

The mechanisms underlying the severe urinary retention induced by acrylamide intoxication were studied in detail in the rat. Subcutaneous treatment with acrylamide monomer (50 mg/kg daily for 10 days) almost completely impaired the micturition reflex, resulting in urinary retention. In fact, the ability to eliminate an oral water load was virtually abolished, while bladder filling with saline (transvesical cystometrogram) failed to activate reflex micturition. Instead, a picture of overflow incontinence resulted in urethane-anaesthetized rats, which was not reversed by intravenous administration of 4-aminopyridine. The nerve-mediated contractile response to field stimulation (0.1–20 Hz, 0.5ms, 60V) of the isolated bladder was unaffected, thus suggesting the integrity of bladder efferent innervation, and no evidence was found from in vitro experiments that the myogenic contractility of the bladder was depressed by acrylamide treatment. Conversely, the sensory nerve-mediated response to capsaicin was abolished and sensory nerve fibres of the bladder were selectively depleted of their content of substance P- and calcitonin gene-related peptide immunoreactivity following acrylamide treatment. In fact, concentrations of the same neuropeptides in other organs, including the adjoining ureters, were unaffected. As to the urethral segment, including the striated sphincter, the d-tubocurarine (0.2 mM)-sensitive urethral response to electrical stimulation (0.1 Hz, 0.1 ms, 20 V) was significantly reduced in acrylamide-treated animals. At the same level, neurofilament protein immunostaining revealed striking accumulations of neurofilament protein-like material in motor end-plates, thus indicating that neuromuscular junctions of the urethral striated sphincter were severely affected. Thus, the afferent arm of the micturition reflex was shown to be severely deranged by acrylamide intoxication, especially in its capsaicin-sensitive component. Since twitch-like contractions of the urethral striated sphincter are probably involved in promoting bladder voiding, a decreased efficiency of this mechanism could participate in the picture of urinary retention induced by acrylamide.

Acrylamide and polyacrylamide: a review of production, use, environmental fate and neurotoxicity.

Acrylamide is a highly water soluble vinyl monomer formed from the hydration of acrylonitrile. The major commercial use of acrylamide is the formation of polymers. In the environment acrylamide has a high mobility in soil, may travel great distances in ground-water, is biodegradable, and is not absorbed by sediments or affected by water treatment. It is absorbed by all routes of animal exposure. The main metabolite is N-acetyl-S-(3-amino-3-oxypropyl)-cysteine and is excreted predominantly in the urine. Acrylamide produces an ascending central/peripheral axonopathy in man and animals. The major histological findings are swelling of axons and/or decrease in number of large diameter axons. Acrylamide axonopathy is reversible with time, but full recovery depends upon the severity of the intoxication. All reported cases of acrylamide toxicity have been attributed to handling the monomer. Polyacrylamide is non-toxic. Specific clinical features of acrylamide intoxication are more conclusive than electrophysiological, histological or biochemical laboratory tests for diagnosis. Acrylamide can be detected by titration, colorimetry, high performance chromatography, gas chromatography and polarography in air, water, biological fluids, tissues and polyacrylamides. Present research on the effects of acrylamide focuses on developmental and reproductive effects, genotoxicity and carcinogenicity.

Vibration sensitivity recovery after a second course of acrylamide intoxication

Five monkeys were trained to report detection of vibration or an electrical stimulus. Three of them had been dosed previously with acrylamide administered orally until toxic signs appeared, and were then allowed to recover. Approximately 30 weeks after the end of the first dosing course, they were dosed a second time with 10 mg/kg/day of acrylamide, 5 days a week, tomimic the dosage regimen of the first dosing period. Two monkeys received vehicle, as in the first dosing period. Vibration sensitivity was reduced in the exposed monkeys to an extent comparable to the first dosing period. Analysis of covariance showed that the rate of recovery from a second exposure to acrylamide was comparable to the rate of recovery from the first exposure. Vibration sensitivity appears useful as a monitoring tool to follow the time course of acrylamide-induced peripheral nerve dysfunction.

Cytoskeletal dynamics in rabbit synovial fibroblasts: I. Effects of acrylamide on intermediate filaments and microfilaments

Rabbit synovial fibroblasts respond to changes in cell shape and cytoskeletal architecture by altering specific gene expression. We have tested the ability of acrylamide, a neurotoxin that alters the distribution of intermediate filaments in cultured PtK1 cells, to induce metalloprotease expression in synovial fibroblasts. Cells treated with 2-20 mM acrylamide for 5 to 24 h underwent shape changes similar to cells treated with the tumor promoter phorbol myristate acetate. Intermediate filaments visualized with anti-vimentin antibodies did not collapse into a perinuclear cap in these rounded cells, but were still present in the extended cell processes. Unexpectedly, when actin was visualized in acrylamide-treated cells, extensive dissociation and clumping of microfilaments was observed. Concentrations of acrylamide greater than 10 mM were cytotoxic, but cells recovered completely after 24 h incubation with 5 mM acrylamide. Like other agents that alter cell shape and actin distribution in synovial fibroblasts, acrylamide also induced expression of the secreted metalloprotease collagenase. Although some recent evidence suggests that acrylamide may be able to exert its collagenase-inducing effects extracellularly, perhaps through transmembrane matrix receptors, our observation that this neurotoxin dramatically alters protein synthesis in synovial fibroblasts suggests that direct effects on cell metabolism may also play a role in acute acrylamide intoxication.

Vibration Sensitivity Recovery after a Second Course of Acrylamide Intoxication

Vibration Sensitivity Recovery after a Second Course of Acrylamide Intoxication

Selective degeneration of the parvocellular-projecting retinal ganglion cells in a New World monkey, Saimiri sciureus

Selective degeneration of retinal ganglion cells projecting to parvocellular layers of the dorsal lateral geniculate nucleus (LGN) was observed in squirrel monkeys ( Saimiri sciureus) exposed to a range of doses of acrylamide monomer. Similar acrylamide-induced neuronal loss has previously been reported in parvocellular-projecting ganglion cells of macaques, but no such selective degeneration has been found in acrylamide-dosed rats, squirrels, rabbits or cats. The extent of ganglion cell loss observed in the present study suggests that in the squirrel monkey, as in the macaque, a majority of ganglion cells project to parvocellular layers of the LGN. The locus of optic tract degeneration suggests that the squirrel monkey parvocellular pathway passes in dorsolateral optic tract, as does that of the macaque. Patterns of decreases in cytochrome oxidase activity confirm that, in both of these primates, geniculocorticol pathways driven by these vulnerable neurons project to corticol layers 4A and 4Cβ. These results suggest close parallels in the neuroanatomical projections and toxic vulnerability of the parvocellular-projecting pathway in New and Old World monkeys. They indicate that acrylamide intoxication can be used to selectively damage this pathway in order to study the functional roles of parallel visula pathways in both New and Old World monkeys.

Neurological and electroneuromyographic assessment of the adverse effects of acrylamide on occupationally exposed workers.

Seventy-one acrylamide workers and fifty-one unexposed referents were studied. Weak legs and numb hands and feet, preceded by skin peeling from the hands, were the early symptoms of the acrylamide workers; their early signs were impairment of vibration sensation in their toes and loss of ankle reflexes. Three cases had cerebellar involvement followed by polyneuropathy due to heavy exposure. Electroneuromyographic changes, including a decrease in the sensory action potential amplitude, neurogenic abnormalities in electromyography, and prolongation of the ankle tendon reflex latency, are of greater importance in the early detection of acrylamide neurotoxicity since they can precede the neuropathic symptoms and signs. The diagnostic criteria for occupational acrylamide intoxication of this study revealed three severe poisonings, six moderate poisonings, and 43 mild poisonings. The total prevalence of acrylamide poisoning was 73.2%. The prevention of dermal exposure to acrylamide should be emphasized.

Neurofilament antigens in acrylamide neuropathy.

After repeated exposure, acrylamide (AC) produces degeneration of distal axons. Because neurons whose axons have been injured (e.g. by axotomy) show alterations in their structural and chemical properties, the present study was designed to differentiate the direct effects of AC intoxication from neuronal responses secondary to axonal injury caused by AC. Rats were given AC as either a single high dose (75 mg/kg), or as daily intraperitoneal injections (30 mg/kg, six days per week for four weeks). Dorsal root ganglia of the fifth lumbar level, L5, were examined using a variety of monoclonal antibodies directed against nonphosphorylated (2-135) and phosphorylated (03-44, 06-17, 07-05) epitopes of 145 and 200 kilodalton neurofilament proteins. In control rats, antibody 2-135 stained axons and neuronal cell bodies; antibodies against phosphorylated epitopes of neurofilaments stained only axons distal to the glomerulus. Following chronic AC intoxication, all three antibodies directed against phosphorylated epitopes of neurofilaments (particularly 07-05) demonstrated intense immunoreactivity in 20-30% of neuronal cell bodies. In addition, the glomerular region of these axons was stained. Electron microscopy revealed many chromatolytic cells containing few neurofilaments. In contrast, a single high dose of AC produced no abnormal staining of neuronal cell bodies at a time when slow axonal transport was impaired. Our findings are compared to those observed following axotomy and to those occurring in aluminum-intoxicated rabbits, two experimental disorders in which altered distributions of phosphorylated filaments have been documented.

Acrylamide Neuropathy: Changes in the Composition of Proteins of Fast Axonal Transport Resemble Those Observed in Regenerating Axons

Proteins conveyed by fast axonal transport along sensory and motor axons of rat sciatic nerve were labelled with L-[35S]methionine and characterized by one- and two-dimensional electrophoresis on polyacrylamide gels, followed by fluorography. Nerves from normal or bis-acrylamide-treated animals were compared with nerves from acrylamide-treated animals and nerves regenerating after a crush axotomy. In both sensory and motor axons significant changes in the pattern of labelled bands on one-dimensional gels occurred after 10 days of acrylamide treatment (50 mg/kg daily, i.p.). These changes resembled those seen in regenerating axons, but were less pronounced. No changes were detectable after shorter periods of treatment, even though the onset of the neuropathy, assessed by a behavioral test, occurred on days 4-6 of treatment. Two-dimensional separations of the labelled proteins revealed increased labelling of growth-associated protein 43 in acrylamide-treated animals, but again this was less pronounced than in regenerating nerves. Acrylamide treatment induces changes in composition of fast-transported protein that are qualitatively similar to those seen after axotomy. Since these changes are not detectable until the neuropathy is advanced, it is unlikely that they are causative factors. Instead, they are most likely a result of the cell body reaction previously observed in acrylamide intoxication, a reaction that resembles that produced by axotomy.

Evaluation of Occupational Acrylamide Exposures

Abstract Since commercial production of acrylamide began in 1954, there have been at least 60 reported cases of acrylamide poisoning resulting in peripheral neuropathy in workers. All of these cases except one have involved occupational exposure to acrylamide monomerfrom either acrylamide and/or Polyacrylamide manufacturing, or acrylamide grouting. Because of a lack of adequate exposure data for these reported cases of acrylamide intoxication and for current work environment conditions, investigators from the National Institute for Occupational Safety and Health have undertaken a study to evaluate exposures in four acrylamide-polyacrylamide manufacturing plants and atone sewergrouting site. Ninety-one personal eight-hourtime-weighted average (TWA) exposures from 81 workers in the manufacturing plants had airborne acrylamide levels ranging from 0.001 to 0.392 mg/m3 with a geometric mean of 0.036 mg/m3. The mean exposure level for monomer operators was 0.065 mg/m3; polymer operators, 0.031 mg/m3; and mainte...

Slow axonal transport in acrylamide neuropathy: different abnormalities produced by single-dose and continuous administration

Alterations in axonal caliber and neurofilament content have been associated with altered neurofilament transport in several models of neurofibrillary degeneration. Acrylamide intoxication provides a prototype of distal axonal degeneration, the most frequent pattern of axonal pathology in human and experimental neurotoxic injury. Neurofibrillary changes are a variable and often minor aspect of the early pathological changes observed in acrylamide intoxication, and previous studies of slow axonal transport have produced conflicting results. In this study, we have correlated slow axonal transport, specifically neurofilament transport, with structural changes in the sciatic nerve complex of rats exposed to acrylamide. To study direct toxic effects of acrylamide, young rats were given a single dose of acrylamide (75 mg/kg, i.p.). A second group received daily injections of acrylamide at a lower dose (30 mg/kg, i.p.) in order to study animals with established acrylamide neuropathy. The slow component of axonal transport was labeled by intraspinal injections of [35S] methionine. Transport of individual slow component polypeptides was compared to profiles obtained from age-matched controls. Similarly intoxicated rats were perfused for morphometric and morphological studies. Results demonstrate that two different abnormalities of the slow component of axonal transport arise at different stages during the development of experimental acrylamide neuropathy. Both patterns of altered transport have structural correlates which reflect the changes in neurofilament transport. Following a single high dose, there was a modest retardation of the leading edge of the slow component. At this time, neurofilaments accumulated in proximal axons with formation of axonal swellings. During chronic administration, when distal axonal degeneration was present, the proportion of neurofilaments in the slow component was markedly reduced, and there was prominent loss of caliber in proximal axons. We suggest that these early changes represent a direct toxic effect of acrylamide on slow transport, whereas the later changes reflect reordering of slow transport as a neuronal response to toxin-induced axonal injury. This latter effect is of sufficient magnitude to obscure the acrylamide-induced retardation of slow transport.

Autoradiographic changes of3H‐α‐bungarotoxin binding in rat hind limb muscles after a cryoinjury of the sciatic nerve and in acrylamide intoxication

The morphological distribution of acetylcholine receptors in rat tibialis anterior and soleus muscles after a cryoinjury of the sciatic nerve was studied by in vitro autoradiography with 3H-alpha-bungarotoxin (3H-alpha-Btx). Tibialis anterior from rats intoxicated with acrylamide was also investigated by this technique. A computer system was used for densitometry and colour coding of the autoradiographs. In normal muscle, 3H-alpha-Btx binding was observed only at the motor endplates. From the second day after the nerve lesion the area of binding spread from the motor endplate region towards the muscle-tendon regions and on the 16th day almost all parts of the muscles showed increased binding. The binding had begun to decrease in the middle parts of the muscles on the 20th day and on the 30th day binding was observed only in the motor endplate area. Tibialis anterior from rats intoxicated with acrylamide (total dose 1100 mg X kg-1) showed 3H-alpha-Btx binding over the entire muscle.

Neurotoxic effects of acrylamide on rat retinogeniculate fibres

The common laboratory chemical, acrylamide, causes various clinical effects including dysfunction of the visual system. Previous electrophysiological recordings from the rat lateral geniculate nucleus (LGN) following exposure to acrylamide suggested that X-like cells were selectively disrupted by the neurotoxin. This study examines the possibility that the diameter of the optic tract fibres may underlie their differential susceptibility, but shows that fibres of all sizes are affected by acrylamide intoxication and the results suggest that the selective effect of acrylamide is not due simply to disruption of optic tract fibres.

Ultrastructural features of the Purkinje cell damage caused by acrylamide in the rat: a new phenomenon in cellular neuropathology.

Dosing rats with acrylamide leads to the formation in Purkinje cells of juxtanuclear clusters of tubular and vesicular smooth endoplastic reticulum (SER). A microtubule organizing centre forms in relation to these clusters and together they appear to move to the cell surface, where protrusions of plasmalemma form, often with overlying synaptic attachments, containing densely packed tubular and vesicular SER membranes. Usually the microtubule organizing centre immediately underlies this. Subsequently, appearances suggest that astroglial intrusions occur internal to the protrusions described above to which the tubulo-vesicular material appears to be transferred. During these events the organization of the cytoplasm of the Purkinje cell is grossly disturbed with apparent loss and disarray of rough endoplasmic reticulum (RER) and of polyribosomes. This temporal sequence of events can be followed after a single dose of acrylamide. In chronically intoxicated animals vacuolation and swelling of dendrites takes place and the Purkinje cell may die after all stages of the cellular transformations have been present. These unique events appear to be confined to Purkinje cells and are considered probably to be the result of a primary disturbance to SER synthesis caused by acrylamide. It is argued that the changes taking place in acrylamide intoxication in neurons that lead to degeneration in long axons are probably of the same general kind.

Anterograde axonal transport in rats during intoxication with acrylamide.

Abstract: Anterograde axonal transport was examined in sensory nerves of rats intoxicated with a low dose (group I) or a high dose (group II) of acrylamide. After injection of either [35S]methionine and [3H]fucose or [3H]proline into the dorsal root ganglia of the 5th lumbar roots, distribution of protein label was measured in 3‐mm segments of the sciatic nerve at intervals of 2 h, 4 h, 10 days, and 26 days. No difference in ganglion incorporation was present at 4 h, and the fast transport velocity of methionine label also remained normal [14.7 ± 1.3 mm/h (mean ± SD) in controls versus 14.6 ± 0.3 mm/h and 15.4 ± 1.2 mm/h in acrylamide group I and II, respectively]. Neither was there any decrease in transport velocity of proline label of slow component b (4.18 ± 0.29 mm/day in controls versus 4.29 ± 0.17 mm/d and 4.22 ± 0.29 mm/day in acrylamide group I and II, respectively). In slow component a, however, a significant reduction in the fractional amount of proline label was found (20.8 ± 4.0% in controls versus 17.6 ± 14.9% and 9.7 ± 5.9% in acrylamide group I and II, respectively). Again no decrease in transport velocity was observed (1.03 ± 0.02 mm/day in controls versus 1.06 ± 0.08 mm/day and 1.07 ± 0.03 mm/day in acrylamide group I and II, respectively), and closer inspection of the activity along the nerve did not reveal any alteration in skewness or ‘peakedness’ of the distribution curve. The reduction in amount of protein carried in the slow axonal transport component in rats with severe acrylamide neuropathy (group II) could be associated with fibre breakdown at a late stage of the neuropathic process. The most important consequence of the study is, however, that in contrast to previous suggestions, during acrylamide intoxication no changes are present in protein incorporation or in anterograde axonal transport which can explain the initial pathological or functional abnormalities of the distal axons.

Early and dose-dependent decrease of retrograde axonal transport in acrylamide-intoxicated rats.

The effect of retrograde axonal transport of doses of acrylamide ranging from 50 to 500 mg/kg was studied in sensory nerve of rats. Accumulation of trichloroacetic acid-phosphotungstic acid-insoluble label was measured in a collection segment distal to a double ligature placed on the sciatic nerve at intervals 9-15 h and 9-24 h following injection into the dorsal root ganglion of the fifth lumbar root of [35S]methionine and [3H]fucose. After a dose of 100 mg/kg of acrylamide no neurological signs of neuropathy had yet appeared, but retrograde buildup of protein label was significantly reduced for the long interval (2.20 +/- 0.49 arbitrary units (AU) (mean +/- SD) versus 2.81 +/- 0.57 AU in controls, 2p = 0.034). No abnormality of the short interval appeared before a dose of 500 mg/kg was reached. The retrograde transport abnormality was dose-related (r = -0.85, n = 28, and 2p = 1.2 x 10(-8)), as was the degree of neuropathy evaluated by "blind" neurological scoring (r = 0.88, n = 14, and 2p = 2.8 x 10(-5)). After a dose of 500 mg/kg, when the rats were severely disabled with almost total incoordination of the hindlegs, the retrograde accumulation of the long interval was profoundly depressed (1.08 +/- 0.28 AU versus 2.81 +/- 0.57 AU in controls, 2p = 1.2 x 10(-7)). Similar changes were seen in accumulation of glycoprotein label. After the rats had recovered for 4-10 weeks neurological signs of neuropathy had disappeared and the transport abnormality had improved. To test the specificity of acrylamide on the retrograde transport defect N-hydroxymethylacrylamide and methylene-bisacrylamide, which do not induce neuropathy, were studied. None of these related compounds influenced the transport. These observations imply that in acrylamide intoxication a defect in the amount of material carried by retrograde axonal transport rather than in "turnaround" time or in transport velocity is present, that the transport abnormality precedes the development of neuropathy, and that it is related to the degree of the neurological disability. We suggest that the retention of protein in the distal axons in the functional counterpart of the well-known accumulation of vesicular organelles in the preterminals.

Hind limb somatosensory evoked potentials in the monkey: The effects of distal axonopathy

Computer-averaged short-latency somatosensory evoked potentials (SLSEP) to unilateral stimulation of the peroneal nerve were recorded from surface electrodes overlying the peripheral nerve, cauda equina, spinal cord, brainstem, and contralateral sensorimotor region. Seven monkeys were studied under normal conditions and at various stages of distal axonopathy induced by systematic acrylamide intoxication. With the use of a noncephalic reference, a series of five small-amplitude positive components were identified that precede the initial cortical activity. On the basis of timing and topography of the components, the source of the first one, SLSPEP1, was localized to the lumbar dorsal root fibers and that of the second, SLSEP2, to the ascending spinal tracts, principally gracile fasciculus. Bipolar recordings of the SLSEP2 overlying the rostral extreme of the cervical spinal cord provided a sensitive measure of the onset of distal axonopathy. Changes in the timing of this component antedated both abnormalities of spinal or peripheral nerve conduction and behavioral signs of intoxication. The initial alteration was specific to stimulation of the hind limb and was associated with early morphological change limited to the terminal and preterminal portions of the long axons in the gracile fasciculus.

The Effect of Methylcobalamin on the Experimental Acrylamide Neuropathy

This study was designed to evaluate the effect of methylcobalamin on the myelinated fiber degeneration produced by acrylamide intoxication in rats. Twelve Sprague-Dawley rats were fed a stock diet with water containing 500ppm acrylamide ad libitum for three weeks. During additional three weeks, the acryl amide was withdrawn.Methylcobalamin, 500μg/kg, was intramuscularly administered to 6 rats as the test and 0.675% NaCl solution was intramuscularly administered to 6 rats as the control for the period of 6 weeks. All rats developed a waddling and paretic gait after twelve days of intoxication. In the control, two rats died on the 19 th and 20th days of intoxication, respectively. No rats died in the test. Three test and two control rats were sacrificed at a time, and both the sural and the peroneal nerves harvested were processed for morphometric studies at the end of the 3rd and 6th weeks of the experiment.In teased fiber analysis the frequency of axonal degeneration of myelinatedfibers was lower in tests than in control rats for each of four different nerves (the proximal, at midthigh, and distal, at ankle, sural nerves and proximal, at mid thigh, and distal, at knee, peroneal nerves). It was significantly lower in test than in control rats (p<0.02) in the combined test of the four different nerves. Although the density of myelinated fibers was higher in test than in control rats, the difference between the test and control rats was not significant. The total number of myelinated fibers in test rats was significantly greater than in control rats for both proximal and distal sural nerves (p<0.05 and p<0.01).The data suggested that methylcobalamin may have played a protective role against the axonal degeneration and subsequent loss of myelinated fibers in acrylamide neuropathy of rats.

Effect of acrylamide intoxication on pyridine nucleotide concentrations and functions in rat cerebral cortex

Male rats were given cumulative doses of 428 mg/kg (low dose) and 668 mg/kg (high dose) of acrylamide. Concentrations of oxidized pyridine nucleotides were determined in samples of cerebral cortex from treated and control rats. The concentration of NAD + was significantly increased (P < 0.01) in brains from the high dose animals. The function of pyridine nucleotides was evaluated by measuring substrates of pyridine nucleotide-dependent enzymes both in immediately frozen cerebral cortex and in cortices subjected to ischemia, by measuring total high-energy phosphate and the rate of its use during ischemia, and by determining the cytoplasmic redox state of pyridine nucleotides from enzyme equilibrium constants and measured substrate levels. α-Glycerophosphate was significantly elevated in the brains from the high dose animals (P < 0.05), while other measured substrates were unchanged. Changes in substrate concentrations during ischemia were similar in cerebral cortices from controls and treated rats and did not suggest interference by acrylamide with coenzyme function. Total highenergy phosphate sources were unchanged in treated animals and the rate of their use during ischemia was the same as that of controls. Calculation of the redox state of cytoplasmic pyridine nucleotides suggested that both NAD and NADP may be more in the reduced form in cerebral cortices of treated animals than in controls; however, these changes were small compared to redox changes under other conditions. While acrylamide increased the concentration of NAD + in cerebral cortices from treated rats, there was little suggestion of an interference with pyridine nucleotide function.