Distribution Of Catecholamines Research Articles

Factors Influencing Postmortem Catecholamine Level and Its Correlations With Agony Time and Cause of Death in Medicolegal Autopsy.

Catecholamines consisting of epinephrine (EP), norepinephrine (NE), and dopamine (DA) are known as a class of chemical neurotransmitters and hormones essential for regulation of physiological processes including stress responses. Many researchers have tried to establish a relationship between postmortem catecholamine level and agony time or underlying cause of death. However, relevant studies have yielded debatable results. This study was performed to determine characteristics of catecholamine distribution in postmortem specimens with various influencing factors and to assess relationships of postmortem catecholamine levels with agony time and cause of death. A total of 114 autopsy cases were analyzed for catecholamine levels and EP/NE ratios in femoral blood, heart blood, and urine specimens. Postmortem catecholamine levels according to sex, age, medical treatments (cardiopulmonary resuscitation [CPR] and EP injection), postmortem interval (PMI), agonal period, manner of death, and cause of death were evaluated. Close mutual relationships were noted among femoral and heart blood catecholamine levels. There was no correlation between blood and urine catecholamine levels. Catecholamine levels showed no significant differences according to sex, age, or manner of death. Heart EP and heart EP/NE ratio were significantly higher in the group with CPR. Femoral DA, heart EP, heart NE, heart DA, and urine DA were significantly increased in the group with EP injection. Urine NE and urine DA showed significant differences among PMI groups, with both increased over PMI. In correlation analysis, femoral DA and urine NE displayed weak correlations with PMI. Regarding agony time, femoral and heart DA were significantly increased in long agony group compared to those in the short agony group. With regard to the cause of death, multiple comparison analysis for major categories (natural death, injury, intoxication, asphyxia, drowning, and fire death) revealed a significant increase of femoral NE in asphyxia in comparison with injury. In subgroup analysis for the group without EP injection, femoral NE (P = 0.048), femoral DA (P = 0.039), and heart EP (P = 0.021) showed significant differences between PMI groups. Results of this study have important implications for understanding postmortem catecholamine distribution and their mutual associations, influences of clinical and demographic factors, and relationships with agony time and cause of death in Korean population. Although comprehensive demonstration of catecholamine level as stress index was not possible in the present study, the assessment of postmortem catecholamine levels could be used as a supportive tool in classification of agonal status and differential diagnosis of the cause of death in particular cases. Further investigation is needed on this issue.

Signaler’s Vasotocin Alters the Relationship between the Responder’s Forebrain Catecholamines and Communication Behavior in Lizards (Anolis carolinensis)

Dynamic fluctuations in the distribution of catecholamines across the brain modulate the responsiveness of vertebrates to social stimuli. Previous work demonstrates that green anoles (Anolis carolinensis) increase chemosensory behavior in response to males treated with exogenous arginine vasotocin (AVT), but the neurochemical mechanisms underlying this behavioral shift remains unclear. Since central catecholamine systems, including dopamine, rapidly activate in response to social stimuli, we tested whether exogenous AVT in signalers (stimulus animals) impacts catecholamine concentrations in the forebrain (where olfactory and visual information are integrated and processed) of untreated lizard responders. We also tested whether AVT influences the relationship between forebrain catecholamine concentrations and communication behavior in untreated receivers. We measured global catecholamine (dopamine = DA, epinephrine = Epi, and norepinephrine = NE) concentrations in the forebrain of untreated responders using high-performance liquid chromatography-mass spectrometry following either a 30-min social interaction with a stimulus male or a period of social isolation. Stimulus males were injected with exogenous AVT or vehicle saline (SAL). We found that global DA, but not Epi or NE, concentrations were elevated in lizards responding to SAL-males relative to isolated lizards. Lizards interacting with AVT-males had DA, Epi and NE concentrations that were not significantly different from SAL or isolated groups. For behavior, we found a significant effect of social treatment (AVT vs. SAL) on the relationships between (1) DA concentrations and the motivation to perform a chemical display (latency to tongue flick) and (2) Epi concentrations and time spent displaying mostly green body coloration. We also found a significant negative correlation between DA concentrations and the latency to perform a visual display but found no effect of social treatment on this relationship. These data suggest that catecholamine concentrations in the forebrain of untreated responders are associated with chemical and visual communication in lizards and that signaler AVT alters this relationship for some, but not all, aspects of social communication.

Distribution and gene expression of neuropeptides during brain development

Neuropeptides and catecholamines are biologically active substances which play the roles of neurotransmitters, neuromodulators and cotransmitters in the central nervous system (CNS). These substances are known to regulate and influence a wide spectrum of functions; such as food and water intake, thermoregulation, growth and maturation, sexual behaviour, reproduction, function of the hypothalamic-hypophysial-organ axes, and many others. This large family of neuropeptides is comprised of around 40 fundamental polypeptides, which does not include their derivatives and related peptides. Localization and development of several of them was intensively studied in the brain of a wide range of species, including the rat and the pig. In this present paper, data regarding distribution of catecholamine synthesising enzymes and some neuropeptides, as well as their gene expression during development in the rodent and porcine brain are summarised and related to development of LHRH-containing structures.

Effects of Bone Marrow Autotransplantation on the Bone Marrow Neurotransmitter Structures.

Morphological structures involved in local regulation of tissue processes and the neurotransmitters they produce are assumed to play an important role in the pathogenesis of oncological diseases. We studied the dynamics of neurotransmitter cell counts and distribution of catecholamines and serotonin in them and analyzed proliferative activity of hemopoietic cells in the bone marrow of mice after bone marrow autotransplantation. The bone marrow of male mice was studied by fluorescent and immunohistochemical methods after injection of the bone marrow from the same mouse into the caudal vein. The count of neurotransmitter cells and the cell proliferation index increased after bone marrow autotransplantation.

Nanopore Opening at Flat and Nanotip Conical Electrodes during Vesicle Impact Electrochemical Cytometry.

The oxidation of catecholamine at a microelectrode, following its release from individual vesicles, allows interrogation of the content of single nanometer vesicles with vesicle impact electrochemical cytometry (VIEC). Previous to this development, there were no methods available to quantify the chemical load of single vesicles. However, accurate quantification of the content is hampered by uncertainty in the proportion of substituent molecules reaching the electrode surface (collection efficiency). In this work, we use quantitative modeling to calculate this collection efficiency. For all vesicles except those at the very edge of the electrode, modeling shows that ∼100% oxidation efficiency is achieved when employing a 33 μm diameter disk microelectrode for VIEC, independent of the location of the vesicle release pore. We use this to experimentally determine a precise distribution of catecholamine in individual vesicles extracted from PC12 cells. In contrast, we calculate that when a nanotip conical electrode (∼4 μm length, ∼1.5 μm diameter at the base) is employed, as in intracellular VIEC (IVIEC), the current-time response depends strongly on the position of the catecholamine-releasing pore in the vesicle membrane. When vesicle release occurs with the pore opening occurring far from the electrode, lower currents and partial oxidation (∼75%) of the catecholamine are predicted, as compared to higher currents and ∼100% oxidation, when the pore is close to/at the electrode surface. As close agreement is observed between the experimentally measured vesicular content in intracellular and extracted vesicles from the same cell line using nanotip and disk electrodes, respectively, we conclude that pores open at the electrode surface. Not only does this suggest that electroporation of the vesicle membrane is the primary driving force for catecholamine release from vesicles at polarized electrodes, but it also indicates that IVIEC with nanotip electrodes can directly assess vesicular content without correction.

Identification and distribution of neuronal nitric oxide synthase and neurochemical markers in the neuroepithelial cells of the gill and the skin in the giant mudskipper, Periophthalmodon schlosseri

Mudskippers are amphibious fishes living in mudflats and mangroves. These fishes hold air in their large buccopharyngeal-opercular cavities where respiratory gas exchange takes place via the gills and higher vascularized epithelium lining the cavities and also the skin epidermis. Although aerial ventilation response to changes in ambient gas concentration has been studied in mudskippers, the localization and distribution of respiratory chemoreceptors, their neurochemical coding and function as well as physiological evidence for the gill or skin as site for O2 and CO2 sensing are currently not known. In the present study we assessed the distribution of serotonin, acetylcholine, catecholamines and nitric oxide in the neuroepithelial cells (NECs) of the mudskipper gill and skin epithelium using immunohistochemistry and confocal microscopy. Colocalization studies showed that 5-HT is coexpressed with nNOS, Na+/K+-ATPase, TH and VAChT; nNOS is coexpressed with Na+/K+-ATPase and TH in the skin. In the gill 5-HT is coexpressed with nNOS and VAhHT and nNOS is coexpressed with Na+/K+-ATPase and TH. Acetylcholine is also expressed in chain and proximal neurons projecting to the efferent filament artery and branchial smooth muscle. The serotonergic cells c labeled with VAChT, nNOS and TH, thus indicating the presence of NEC populations and the possibility that these neurotransmitters (other than serotonin) may act as primary transmitters in the hypoxic reflex in fish gills. Immunolabeling with TH antibodies revealed that NECs in the gill and the skin are innervated by catecholaminergic nerves, thus suggesting that these cells are involved in a central control of branchial functions through their relationships with the sympathetic branchial nervous system. The Na+/K+-ATPase in mitochondria-rich cells (MRCs), which are most concentrated in the gill lamellar epithelium, is colabeled with nNOS and associated with TH nerve terminals. TH-immunopositive fine varicosities were also associated with the numerous capillaries in the skin surface and the layers of the swollen cells. Based on the often hypercapnic and hypoxic habitat of the mudskippers, these fishes may represent an attractive model for pursuing studies on O2 and CO2 sensing due to the air-breathing that increases the importance of acid/base regulation and the O2-related drive including the function of gasotransmitters such as nitric oxide that has an inhibitory (regulatory) function in ionoregulation.

Accumulation of radioactivity after repeated infusion of 3H-adrenaline and 3H-noradrenaline in the rat as a model animal

Besides enzymatic inactivation, catecholamines bind non-enzymatically and irreversible to proteins. The physiological impact of these catecholamine adducts is still unclear. We therefore collected basic data about the distribution of catecholamine adducts in the rat after repeated intravenous administration of 3H-adrenaline and 3H-noradrenaline.In all animals radioactivity in blood increased until the last injection on Day 7 and decreased then slowly close to background values (plasma) or remained higher (erythrocytes). In all sampled tissues radioactivity could be found, but only in hair high amounts remained present even after 3 weeks. Half-life of rat serum albumin loaded with 3H-adrenaline or 3H-noradrenaline was not altered.This study provides basic knowledge about the distribution of catecholamines or their adducts, but physiological effects could not be demonstrated. However, for the first time deposition and accumulation of catecholamines (adducts) in the hair could be proven, suggesting that hair might be used for evaluating long term stress.

PM.90 Incidental Phaeochromocytoma in Pregnancy

IntroductionPhaeochromocytoma, a catecholamine-producing endocrine tumour, is a life-threatening condition to the mother and fetus. The incidence of phaeochromocytoma in pregnancy is extremely rare, 1 in 54 000 pregnancies1. If it...

Distribution of acetylcholine and catecholamines in fish gills and their potential roles in the hypoxic ventilatory response

Carotid body glomus cells in mammals contain a plethora of different neurochemicals. Several hypotheses exist to explain their roles in oxygen-chemosensing. In the present study we assessed the distribution of serotonin, acetylcholine and catecholamines in the gills of trout (Oncorhynchus mykiss) and goldfish (Carassius auratus) using immunohistochemistry, and an activity-dependent dye, Texas Red hydrazide (TXR). In fish the putative oxygen sensing cells are neuroepithelial cells (NECs) and the focus in recent studies has been on the role of serotonin in oxygen chemoreception. The NECs of trout and goldfish contain serotonin, but, in contrast to the glomus cells of mammals, not acetylcholine or catecholamines. Acetylcholine was expressed in chain and proximal neurons and in extrinsic nerve bundles in the filaments. The serotonergic NECs did not label with the HNK-1 antibody suggesting that if they are derived from the neural crest, they are no longer proliferative or migrating. Furthermore, we predicted that if serotonergic NECs were chemosensory, they would increase their activity during hypoxia (endocytose TXR), but following 30min of hypoxic exposure (45Torr), serotonergic NECs did not take up TXR. Based on these and previous findings we propose several possible models outlining the ways in which serotonin and acetylcholine could participate in oxygen chemoreception in completing the afferent sensory pathway.

Cardiovascular Catecholamine Receptors in Children: Their Significance in Cardiac Disease

Adrenoceptors and dopamine receptors are grouped together under the name 'catecholamine receptors.' Catecholamines and catecholaminergic drugs act on catecholamine receptors located on or near the cardiovascular system. The physiological effects of catecholamine receptor stimulation are only partly understood. The catecholaminergic drugs used in critical care medicine today are not selective, or are, at best, in part selective for the various catecholamine receptor subtypes. Many patients, however, depend on them. A variety of animal models has been developed to unravel catecholamine distribution and function. However, the identification of species heterogeneity makes it imperative to determine catecholamine receptor distribution and function in humans. In addition, age-related alterations in catecholamine receptor distribution and function have been identified in human adults. This might have implications for our understanding of the effect of catecholamines in pediatric patients. This article will focus on the pediatric population and will review currently available in vitro data on the distribution and the function of catecholamine receptors in the cardiovascular system of fetuses and children. Also discussed are relevant young animal models and in vivo hemodynamic effects of cardiotonic drugs acting on the catecholamine receptor in children requiring major cardiac surgery. A better understanding of these topics might provide clues for new, receptor subtype-selective, therapeutic approaches in newborns and children with cardiac disease.

The catecholaminergic nerve plexus of Holothuroidea

Catecholamines have been extensively reported to be present in most animal groups, including members of Echinodermata. In this study, we investigated the presence and distribution of catecholaminergic nerves in two members of the Holothuroidea, Holothuria glaberrima (Selenka, 1867) (Aspidochirotida, Holothuroidea) and Holothuria mexicana (Ludwig, 1875) (Aspidochirotida, Holothuroidea), by using induced fluorescence for catecholamines on tissue sections and immunohistochemistry with an antibody that recognizes tyrosine hydroxylase. The presence of a catecholaminergic nerve plexus similar in distribution and extension to those previously reported in other members of Echinodermata was observed. This plexus, composed of cells and fibers, is found in the ectoneural component of the echinoderm nervous system and is continuous with the circumoral nerve ring and the radial nerves, tentacular nerves, and esophageal plexus. In addition, fluorescent nerves in the tube feet are continuous with the catecholaminergic components of the radial nerve cords. This is the first comprehensive report on the presence and distribution of catecholamines in the nervous system of Holothuroidea. The continuity and distribution of the catecholaminergic plexus strengthen the notion that the catecholaminergic cells are interneurons, since these do not form part of the known sensory or motor circuits and the fluorescence is confined to organized nervous tissue.

Molecular imaging of adrenal gland by desorption electrospray ionization mass spectrometry

Subtle differences in the spatial distributions of closely related compounds including norepinephrine and epinephrine as well multiple lipids are easily distinguished in adult porcine (17 x 8 mm) and rabbit (7 x 4 mm) adrenal glands in a DESI-MS imaging experiment at atmospheric pressure with a spatial resolution of approximately 200 microm. Sensitive and specific detection in the course of DESI imaging discloses details of catecholamine distribution in porcine adrenal medulla and cortex; the average mass of epinephrine interrogated in each pixel is estimated to be about 150 pg. The distribution of ascorbic acid was revealed in the negative ion mode. In addition, the distribution of cholesterol, which cannot be observed using conventional DESI, was obtained using in situ reaction with betaine aldehyde added to the DESI spray while imaging the porcine adrenal gland tissue. Four characteristic types of distributions were observed, with major amounts of the components in the medulla, the cortex, the reticular zone or in the fourth case, being homogeneously distributed. The results agree with and extend information available from histological studies.

Catecholamine distribution in adult rat testis

Catecholamine distribution in the adult rat testis was examined using a sensitive radioenzymatic method. Norepinephrine was present in the capsule and the interstitial fluid, in higher concentrations than dopamine, while in the interstitial cell preparations only norepinephrine was found. Epinephrine was undetectable in all testicular compartments investigated. No catecholamines were found in the seminiferous tubules. Testicular denervation caused a significant decrease in capsular catecholamines, confirming the neural origin of these amines.

Catecholamine-storing Cells at Acupuncture Points of Rabbits

Recent studies have shown that specific sites of the skin related to the acupoints contain a high concentration of catecholamines, especially noradrenaline (NA). Considering this newly discovered property of the acupoints we assumed that heterogeneous distribution of cutaneous catecholamines could be associated with a specific location of catecholamine-storing cells in acupoint sites. In the present work we used an immunohistochemical method and confocal laser scanning microscopy to examine the presence of catecholamine-storing cells at acupoints of rabbits. Double immunofluorescence staining with antibodies against adrenaline and NA revealed only the cells storing NA in the dermal layer of rabbit skin. NA-storing cells were randomly scattered as single cells as well as existing in small clusters in a globular tissue formation surrounded by blood vessels and capillaries. Microscopic analysis of histological sections also revealed that the distribution of NA-storing cells was closely associated with the location of acupoints. Thus results from our study strongly suggest that acupoint areas of rabbit skin contain catecholamine-storing cells which can release a high level of NA during acupuncture stimulation.

The existence of a linear system consisting of sympathetic endings in rat skin

In a previous pilot study we suggested the novel notion that the catecholaminergic sympathetic nerve endings are non-homogeneously distributed in the rat skin. In the present study we have utilized several independent methods to determine the in vivo distribution of catecholamine-containing fibers in rat skin. Using whole body macro-autoradiography with an iodine125-labeled tyrosine, we localized the distribution of iodine-125-catecholamine in rat skin. The images on the film showed various pairs of symmetrical linear arrays running from the head through the back and to the hind limbs of the animal that we arbitrarily termed sympathetic substance lines (SSLs). The distribution of catecholamine in rat skin was also visualized by light microscopy autoradiography with tritiated tyrosine. The majority of silver grains in the sections were located among hair follicles along a band or zone. Furthermore, a modified sucrose-phosphate-glyoxilic acid (SPG) method was adapted to observe sympathetic fibers in the skin sections. Dense clusters of fluorescent nerve fibers in correspondence of arrector pili muscles (AP muscles) were located along lengthwise lines of the body, in a pattern coinciding with the linear arrays identified by macro-autoradiography. We concluded that concentrated clusters of noradrenergic nerve fibers innervate AP muscles and form a longitudinal linear system in the whole skin. These results are discussed in terms of physiological functions associated with hair follicles, sensory signal pathways and Meridians in Chinese traditional medicine.

Neurotransmitters and neuromodulators during early human development.

Neurotransmitters such as monoamines appear in the embryo before the neurones are differentiated. They may have other functions than neurotransmission during embryogenesis such as differentiation and neuronal growth. For example, serotonin may act as a morphogen. A number of neuropeptides are expressed during ontogenesis, but their function has been difficult to establish. Maybe some of them remain as evolutionary residues. Fast-switching neurotransmitters like the excitatory amino acids and the more ionotropic receptors dominate in the human brain, but appear probably later during evolution as well as during ontogeny. The distribution of catecholamines during development has been analysed with a fluorescence method, while most of the other neurotransmitters have been mapped with immunohistochemical methods. The classical method to determine the physiological role of a neurotransmitter or modulator is to study the physiological effect of its antagonist, blocking the endogenous activity. By transgenic technique, the genes encoding for enzymes involved in the synthesis of neurotransmitters can be knocked-out. Pharmacological blocking of endogenous activity has, for example, demonstrated that adenosine suppresses fetal respiration. Knocking out the dopamine beta-hydroxylase gene results in fetal death, suggesting that noradrenaline is essential for survival. Some neurotransmitters change their effect during embryogenesis, e.g. GABA which is excitatory in the embryo, but inhibitory after birth due to a switch from a high to low chloride content in the nerve cells. It is possible that this is of importance for the wiring of neuronal network in early life. NMDA receptors dominate in the foetus, while kainate and AMPA receptors appear later. At birth, there is a surge of neurotransmitters such as catecholamines, which may be of importance for the neonatal adaptation. Neurotransmitters and modulators are not only important for the neural trafficking in the embryo, but also for the development of the neuronal circuits. Prenatal or neonatal stress (hypoxia), as well as various drugs, may disturb the wiring and cause long-term behavioural effects (fetal and neonatal programming).

Evidence that nerve growth factor promotes the recovery of peripheral neuropathy induced in mice by Cisplatin: behavioral, structural and biochemical analysis

In this study we investigate the neurotoxic action of Cisplatin (6 μg/g body weight for 5 treatment cycles during 15 weeks with a total dose of 30 μg/g), an antitumor drug, and its effect on the level of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in peripheral tissues. We found that Cisplatin in adult rodents impairs peripheral sensory function and both sympathetic and sensory peripheral innervation as shown by the hot-plate response, catecholamine distribution and substance P immunoreactivity respectively. These changes are associated with decreased NGF in intestine, paws, and bladder while NGF increased in the spinal cord. Also BDNF decreased in bladder and paws and increased in spinal cord and intestine. To further investigate the role of NGF in the pathogenesis of Cisplatin-induced peripheral neuropathies a group of animals was injected with NGF (1 μg/g every 4 days for 4 times) following Cisplatin treatment and evaluated for sensory function, sympathetic and sensory innervation and BDNF levels. Data demonstrated that exogenous NGF administration is able to restore biochemical, structural and functional changes induced by Cisplatin. These findings suggest that the reduction of NGF availability could be a cause of Cisplatin-induced peripheral neuropathies and that NGF exogenous administration could prevent or reduce Cisplatin neurotoxicity also in cancer patients, reducing the side effects of chemotherapy.

Localization of tyrosine hydroxylase-immunoreactivity in the brain of the Senegalese sole, Solea senegalensis

The localization of catecholamines in the brain of the Senegalese sole was determined by immunohistochemical techniques using antibodies against tyrosine hydroxylase. Although the general pattern of distribution of catecholamines is consistent with that reported in other teleosts, some remarkable differences are observed. The most rostral tyrosine hydroxylase immunoreactive (TH-ir) cells were identified in the olfactory bulbs, in which a clear asymmetry in the number and location of TH-ir perikarya and fibers was observed. The number of TH-ir cells is manifestly higher in the right olfactory bulb, especially in the internal cell layer. TH-ir fibers are also much more abundant in the right bulb, principally in the glomerular and internal cell layers. Other TH-ir cell masses were identified in the ventral telencephalon, preoptic area, caudoventral hypothalamus, posterior tuberculum, synencephalon, isthmic region and rhombencephalon. Surprisingly, no ir cell bodies were identified in the ventromedial thalamic nucleus, which exhibits a large number of TH-ir cells in other teleosts. The presence of TH-ir fibers in the brain of sole is particularly evident within and around the nuclei in which immunoreactive cells are found. However, other zones such as the dorsal telencephalon, posterior commissure, optic tectum, torus semicircularis, reticular formation or inferior olive also displayed TH-ir fibers. TH-ir axons also enter the infundibulum, reaching the proximal pars distalis of the adenohypophysis. The distribution of TH-ir cells and fibers is compared with that observed in other teleosts and is discussed in a comparative context.

Localisation of biogenic amines in larvae of Bugula neritina (Bryozoa: Cheilostomatida) and their effects on settlement

Distributions of serotonin and catecholamines in larvae of the marine bryozoan Bugula neritina (Bryozoa: Cheilostomatida) were investigated using immunohistochemistry with anti-serotonin antiserum and glyoxylic acid–induced fluorescence histochemistry. Anti-serotonin immunoreactive substances and glyoxylic acid–induced fluorescent substances had similar distributions in the equatorial neuromuscular ring, the neural plexus, the paired axial neuromuscular cords, and tracts connecting the neural plexus to ciliated cells bordering the pyriform organ. The effects of dopamine, noradrenaline, adrenaline, tyramine, octopamine, synephrine and serotonin, at 10−4, 10−5 and 10−6 M, on settlement were analysed. In filtered seawater, 98% of larvae settled in 3 h, but only 11%, 3% and 6% total settlement was observed after 8 h in 10−4 M dopamine, 10−4 M serotonin and 10−5 M serotonin, respectively. Total settlement was 70% in 10−4 M noradrenaline, 80% in 10−4 M adrenaline and 60% in 10−4 M tyramine. Less than 60% settlement was observed in 10−4 and 10−5 M octopamine and synephrine. Serotonin's inhibitory effect on settlement was mimicked by a range of serotonin receptor agonists and antagonists, among which 5-carboxamidotryptamine was the most potent.

The influence of dietary l-azetidine-2-carboxylic acid on catecholamine levels in the hemolymph and cuticle of the corn earworm, Helicoverpa zea

The influence of L-azetidine-2-carboxylic acid (AZC) on catecholamine levels in the hemolymph and cuticle of the corn earworm, Helicoverpa zea, was investigated. Feeding corn earworm larvae on a diet supplemented with AZC significantly reduced hemolymph levels of dopamine (DA) and N-β-alanyldopamine (NBAD) by at least 2–3-fold and to a lesser extent, the levels of N-acetyldopamine (NADA). This suggests that AZC has an inhibitory influence on the mechanisms involved in DA synthesis, catabolism or transport. NBAD was the major catecholamine in both hemolymph and cuticle of H. zea. Catecholamines were generally low in concentration during the larval feeding period but increased to highest levels during larval-pupal transformation. Conversely, catecholamine levels in cuticle were highest on day one of the fifth instar and then decreased to low levels thereafter. NBAD and other catecholamines were higher in day one cuticle of AZC fed larvae than in controls but not thereafter. DA and NBAD concentrations in the cuticle remained low throughout the larval instars, about 5–10 times lower than in the hemolymph. The pattern and temporal distribution of catecholamines during the larval-pupal transformation in this species was such that concentrations remained high in the hemolymph through post-wandering behavior, but low in the cuticle. Catecholamines became abundantly available in the cuticle for pupal sclerotization after pupation had occurred.