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Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons responsible for unintended or uncontrollable movements. Mutations in the leucine-rich repeat kinase 2 locus contribute to genetic forms of PD. The fruit fly Drosophila melanogaster carrying this mutation (LRRK2-Dm) is an in vivo model of PD that develops motor impairment and stands for an eligible non-mammalian paradigm to test novel therapeutic approaches. Dehydrozingerone (DHZ) is a natural phenolic compound isolated from ginger and presents anti-inflammatory, antioxidant and neuroprotective properties, making it a potential therapeutic target for PD. We administered DHZ and its C 2 -symmetric dimer (DHZ-DIM) at 0.5 and 1 mM for 14 and 21 days in the LRRK2-Dm, with the aim of assessing changes in rescuing motor behavior, brain dopaminergic neurons, mitochondria and synapses (T-bars). The shorter treatment with both molecules revealed efficacy at the higher dose, improving climbing behavior with a prevention of dopaminergic neuronal demise. After 21 days, a recovery of the motor disability, dopaminergic neuron loss, mitochondrial damage and T-bars failure was observed with the DHZ-DIM. Our data indicate that the DHZ-DIM exerts a more potent neuroprotective effect with respect to the monomer in LRRK2-Dm, prompting further investigation of these compounds in rodent models of PD.

Loss-of-function mutations in the KCNA1 (Kv1.1) gene cause episodic ataxia type 1 (EA1), a neurological disease characterized by cerebellar dysfunction, ataxic attacks, persistent myokymia with painful cramps in skeletal muscles, and epilepsy. Precision medicine for EA1 treatment is currently unfeasible, as no drug that can enhance the activity of Kv1.1-containing channels and offset the functional defects caused by KCNA1 mutations has been clinically approved. Here, we uncovered that niflumic acid (NFA), a currently prescribed analgesic and anti-inflammatory drug with an excellent safety profile in the clinic, potentiates the activity of Kv1.1 channels. NFA increased Kv1.1 current amplitudes by enhancing the channel open probability, causing a hyperpolarizing shift in the voltage dependence of both channel opening and gating charge movement, slowing the OFF-gating current decay. NFA exerted similar actions on both homomeric Kv1.2 and heteromeric Kv1.1/Kv1.2 channels, which are formed in most brain structures. We show that through its potentiating action, NFA mitigated the EA1 mutation-induced functional defects in Kv1.1 and restored cerebellar synaptic transmission, Purkinje cell availability, and precision of firing. In addition, NFA ameliorated the motor performance of a knock-in mouse model of EA1 and restored the neuromuscular transmission and climbing ability in Shaker (Kv1.1) mutant Drosophila melanogaster flies ( Sh 5 ). By virtue of its multiple actions, NFA has strong potential as an efficacious single-molecule-based therapeutic agent for EA1 and serves as a valuable model for drug discovery.

Introduction: Increased glutamate levels and electrolytic fluctuations have been observed in acutely manic patients. Despite some efficacy of the non-competitive NMDA receptor antagonist memantine (Mem), such as antidepressant-like and mood-stabilizer drugs in clinical studies, its specific mechanisms of action are still uncertain. The present study aims to better characterize the Drosophila melanogaster fly Shaker mutants (SH), as a translational model of manic episodes within bipolar disorder in humans, and to investigate the potential anti-manic properties of Mem., Methods and Results: Our findings showed typical behavioral abnormalities in SH, which mirrored with the overexpression of NMDAR-NR1 protein subunit, matched well to glutamate up-regulation. Such molecular features were associated to a significant reduction of SH brain volume in comparison to Wild Type strain flies (WT). Here we report on the ability of Mem treatment to ameliorate behavioral aberrations of SH (similar to that of Lithium), and its ability to reduce NMDAR-NR1 over-expression., Conclusions: Our results show the involvement of the glutamatergic system in the SH, given the interaction between the Shaker channel and the NMDA receptor, suggesting this model as a promising tool for studying the neurobiology of bipolar disorders. Moreover, our results show Mem as a potential disease-modifying therapy, providing insight on new mechanisms of action., (© 2023 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Background: One of the most challenging tasks of modern biology concerns the real-time tracking and quantification of mRNA expression in living cells. On this matter, a novel platform called SmartFlare TM has taken advantage of fluorophore-linked nanoconstructs for targeting RNA transcripts. Although fluorescence emission does not account for the spatial mRNA distribution, NanoFlare technology has grown a range of theranostic applications starting from detecting biomarkers related to diseases, such as cancer, neurodegenerative pathologies or embryonic developmental disorders., Aim: To investigate the potential of SmartFlare TM in determining time-dependent mRNA expression of prominin 1 ( CD133 ) and octamer-binding transcription factor 4 ( OCT4 ) in single living cells through differentiation., Methods: Brain fragments from the striatum of aborted human fetuses aged 8 wk postconception were processed to obtain neurospheres. For the in vitro differentiation, neurospheres were gently dissociated with Accutase solution. Single cells were resuspended in a basic medium enriched with fetal bovine serum, plated on poly-L-lysine-coated glass coverslips, and grown in a lapse of time from 1 to 4 wk. Live cell mRNA detection was performed using SmartFlare TM probes (CD133, Oct4, Actin, and Scramble). All the samples were incubated at 37 °C for 24 h. For nuclear staining, Hoechst 33342 was added. SmartFlare TM CD133- and OCT4-specific fluorescence signal was assessed using a semiquantitative visual approach, taking into account the fluorescence intensity and the number of labeled cells., Results: In agreement with previous PCR experiments, a unique expression trend was observed for CD133 and OCT4 genes until 7 d in vitro (DIV). Fluorescence resulted in a mixture of diffuse cytoplasmic and spotted-like pattern, also detectable in the contacting neural branches. From 15 to 30 DIV, only few cells showed a scattered fluorescent pattern, in line with the differentiation progression and coherent with mRNA downregulation of these stemness-related genes., Conclusion: SmartFlare TM appears to be a reliable, easy-to-handle tool for investigating CD133 and OCT4 expression in a neural stem cell model, preserving cell biological properties in anticipation of downstream experiments., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)

The search for new disease-modifying drugs for Parkinson's disease (PD) is a slow and highly expensive process, and the repurposing of drugs already approved for different medical indications is becoming a compelling alternative option for researchers. Genetic variables represent a predisposing factor to the disease and mutations in leucine-rich repeat kinase 2 (LRRK2) locus have been correlated to late-onset autosomal-dominant PD. The common fruit fly Drosophila melanogaster carrying the mutation LRRK2 loss-of-function in the WD40 domain (LRRK2 WD40 ), is a simple in vivo model of PD and is a valid tool to first evaluate novel therapeutic approaches to the disease. Recent studies have suggested a neuroprotective activity of immunomodulatory agents in PD models. Here the immunomodulatory drug Pomalidomide (POM), a Thalidomide derivative, was examined in the Drosophila LRRK2 WD40 genetic model of PD. Mutant and wild type flies received increasing POM doses (1, 0.5, 0.25 mM) through their diet from day 1 post eclosion, until postnatal day (PN) 7 or 14, when POM's actions were evaluated by quantifying changes in climbing behavior as a measure of motor performance, the number of brain dopaminergic neurons and T-bars, mitochondria integrity. LRRK2 WD40 flies displayed a spontaneous age-related impairment of climbing activity, and POM significantly and dose-dependently improved climbing performance both at PN 7 and PN 14. LRRK2 WD40 fly motor disability was underpinned by a progressive loss of dopaminergic neurons in posterior clusters of the protocerebrum, which are involved in the control of locomotion, by a low number of T-bars density in the presynaptic bouton active zones. POM treatment fully rescued the cell loss in all posterior clusters at PN 7 and PN 14 and significantly increased the T-bars density. Moreover, several damaged mitochondria with dilated cristae were observed in LRRK2 WD40 flies treated with vehicle but not following POM. This study demonstrates the neuroprotective activity of the immunomodulatory agent POM in a genetic model of PD. POM is an FDA-approved clinically available and well-tolerated drug used for the treatment of multiple myeloma. If further validated in mammalian models of PD, POM could rapidly be clinically tested in humans., (Copyright © 2020 Casu, Mocci, Isola, Pisanu, Boi, Mulas, Greig, Setzu and Carta.)

Within neurodegenerative syndromes, Parkinson's disease (PD) is typically associated with its locomotor defects, sleep disturbances and related dopaminergic (DA) neuron loss. The fruit fly, Drosophila melanogaster ( D. melanogaster ), with leucine-rich repeat kinase 2 mutants ( LRRK2 ) loss-of-function in the WD40 domain, provides mechanistic insights into corresponding human behaviour, possibly disclosing some physiopathologic features of PD in both genetic and sporadic forms. Moreover, several data support the boosting impact of innate and adaptive immunity pathways for driving the progression of PD. In this context, human dialyzable leukocyte extracts (DLE) have been extensively used to transfer antigen-specific information that influences the activity of various immune components, including inflammatory cytokines. Hence, the main goal of our study was to ascertain the therapeutic potential of DLE from male and female donors on D. melanogaster LRRK2 loss-of-function, as compared to D. melanogaster wild-type (WT), in terms of rescuing physiological parameters, such as motor and climbing activities, which are severely compromised in the mutant flies. Finally, in search of the anatomical structures responsible for restored functions in parkinsonian-like mutant flies, we found a topographical correlation between improvement of locomotor performances and an increased number of dopaminergic neurons in selective areas of LRRK2 mutant brains.

Oxidative stress is commonly observed in both idiopathic and genetic cases of Parkinson's disease (PD). It plays an important role in the degeneration of dopaminergic neurons, and it has been associated with altered telomere length (TL). There is currently no cure for PD, and extracts of antioxidative plant, such as Mucuna pruriens and Withania somnifera , are commonly used in Ayurveda to treat patients with PD. In this study, we evaluated 2 enzymatic markers of oxidative stress, glutathione (GSH) system and superoxide dismutase (SOD), and TL in a Drosophila melanogaster model for PD [phosphatase and tensin homolog-induced putative kinase 1 ( PINK1 ) B9 ]. This evaluation was also performed after treatment with the phytoextracts. PINK1 B9 mutants showed a decrease in GSH amount and SOD activity and unexpected longer telomeres compared with wild-type flies. M. pruriens treatment seemed to have a beneficial effect on the oxidative stress conditions. On the other hand, W. somnifera treatment did not show any improvements in the studied oxidative stress mechanisms and even seemed to favor the selection of flies with longer telomeres. In summary, our study suggests the importance of testing antioxidant phytoextracts in a PINK1 B9 model to identify beneficial effects for PD.-Baroli, B., Loi, E., Solari, P., Kasture, A., Moi, L., Muroni, P., Kasture, S., Setzu, M. D., Liscia, A., Zavattari, P. Evaluation of oxidative stress mechanisms and the effects of phytotherapic extracts on Parkinson's disease Drosophila PINK1 B9 model.

Findings from studies using animal models expressing amyotrophic lateral sclerosis (ALS) mutations in RNA-binding proteins, such as Transactive Response DNA-binding protein-43 (TDP-43), indicate that this protein, which is involved in multiple functions, including transcriptional regulation and pre-mRNA splicing, represents a key candidate in ALS development. This study focuses on characterizing, in a Drosophila genetic model of ALS (TDP-43), the effects of Mucuna pruriens (Mpe) and Withania somnifera (Wse). Electrophysiological and behavioural data in TDP-43 mutant flies revealed anomalous locomotion (i.e. impaired climbing with unexpected hyperactivity) and sleep dysregulation. These features, in agreement with previous findings with a different ALS model, were at least partially, rescued by treatment with Mpe and Wse. In addition, electrophysiological recordings from dorsal longitudinal muscle fibers and behavioral observations of TDP-43 flies exposed to the volatile anaesthetics, diethyl ether or chloroform, showed paradoxical responses, which were normalized upon Mpe or Wse treatment. Hence, given the involvement of some potassium channels in the effects of anaesthetics, our results also hint toward a possible dysregulation of some potassium channels in the ALS-TDP-43 Drosophila model, that might shed new light on future therapeutic strategies pertaining to ALS.

The common fruit fly Drosophila melanogaster (Dm) is a simple animal species that contributed significantly to the development of neurobiology whose leucine-rich repeat kinase 2 mutants (LRRK2) loss-of-function in the WD40 domain represent a very interesting tool to look into physiopathology of Parkinson's disease (PD). Accordingly, LRRK2 Dm have also the potential to contribute to reveal innovative therapeutic approaches to its treatment. Withania somnifera Dunal, a plant that grows spontaneously also in Mediterranean regions, is known in folk medicine for its anti-inflammatory and protective properties against neurodegeneration. The aim of this study was to evaluate the neuroprotective effects of its standardized root methanolic extract (Wse) on the LRRK2 loss-of-function Dm model of PD. To this end mutant and wild type (WT) flies were administered Wse, through diet, at different concentrations as larvae and adults (L+/A+) or as adults (L-/A+) only. LRRK2 mutants have a significantly reduced lifespan and compromised motor function and mitochondrial morphology compared to WT flies 1% Wse-enriched diet, administered to Dm LRRK2 as L-/A+and improved a) locomotor activity b) muscle electrophysiological response to stimuli and also c) protected against mitochondria degeneration. In contrast, the administration of Wse to Dm LRRK2 as L+/A+, no matter at which concentration, worsened lifespan and determined the appearance of increased endosomal activity in the thoracic ganglia. These results, while confirming that the LRRK2 loss-of-function in the WD40 domain represents a valid model of PD, reveal that under appropriate concentrations Wse can be usefully employed to counteract some deficits associated with the disease. However, a careful assessment of the risks, likely related to the impaired endosomal activity, is required.

The fruit fly Drosophila melanogaster (Dm) mutant for PTEN-induced putative kinase 1 (PINK1B9) gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD). Using PINK1B9 mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe), a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1B9 mutants, supplied with standard diet to larvae and adults, were assayed on 3-6 (I), 10-15 (II) and 20-25 (III) days old flies. Mpe 0.1% significantly extended lifespan of PINK1B9 and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1B9 of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1%) ameliorated climbing of only PINK1B9 flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1B9 revealed that Mpe restored to wild type (WT) levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP) and tyrosine hydroxylase (TH) expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the properties of Mucuna pruriens for PD treatment.

Parkinson's disease (PD) is one of the most common neurodegenerative disease characterized by the clinical triad: tremor, akinesia and rigidity. Several studies have suggested that PD patients show disturbances in olfaction at the earliest onset of the disease. The fruit fly Drosophila melanogaster is becoming a powerful model organism to study neurodegenerative diseases. We sought to use this system to explore olfactory dysfunction, if any, in PINK1 mutants, which is a model for PD. PINK1 mutants display many important diagnostic symptoms of the disease such as akinetic motor behavior. In the present study, we describe for the first time, to the best of our knowledge, neurophysiological and neuroanatomical results concerning the olfactory function in PINK1 mutant flies. Electroantennograms were recorded in response to synthetic and natural volatiles (essential oils) from groups of PINK1 mutant adults at three different time points in their life cycle: one from 3-5 day-old flies, from 15-20 and from 27-30 days. The results obtained were compared with the same age-groups of wild type flies. We found that mutant adults showed a decrease in the olfactory response to 1-hexanol, α-pinene and essential oil volatiles. This olfactory response in mutant adults decreased even more as the flies aged. Immunohistological analysis of the antennal lobes in these mutants revealed structural abnormalities, especially in the expression of Bruchpilot protein, a marker for synaptic active zones. The combination of electrophysiological and morphological results suggests that the altered synaptic organization may be due to a neurodegenerative process. Our results indicate that this model can be used as a tool for understanding PD pathogensis and pathophysiology. These results help to explore the potential of using olfaction as a means of monitoring PD progression and developing new treatments.

The responses of olive fly (Bactrocera oleae) antennal and palpal olfactory receptors to odors emitted by Pseudomonas putida bacterial filtrate and to volatiles from a host plant were evaluated using electrophysiological and behavioral bioassays. Morphological identification of olfactory receptors was also performed. The third antennal segment (flagellum) bears four types of multiporous sensilla: trichoid, short basiconica, clavate and grooved. Maxillary palps have mechanosensory bristles and multiporous basiconica sensilla. In wind-tunnel bioassays, olive fly responses to volatiles emitted by bacterial filtrate were higher than those to culture medium. Bacterial filtrate was more attractive than ammonium carbonate or a mixture of ethyl acetate and acetic acid in ethanol. GC-MS of bacterial filtrate identified some of the chemicals produced by bacterial activity, including methyl thiolacetate, ammonia, 2-pentanone, 2-heptanone, ethyl tiglate and methyl thiocyanate. Electrophysiological investigations proved that antennal sensilla are responsive to bacterial filtrate odor, methyl thiolacetate, olive leaves and olives, as well as to α-pinene, while acetic acid elicited an inhibitory response. Electropalpgrams recorded a specific response to bacterial filtrate by mated males and females, as well as a dose-dependent response relationship to methyl thiolacetate by mated females. The identification of new active volatile compounds in the semiochemical system of the olive fly is promising for the development of innovative control strategies in area-wide management., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The morphology of the antennal funiculus and the external morphological characteristics and distribution of sensilla of blow fly, Protophormia terraenovae, have been studied using light and scanning electron microscopy. Cross section of the funiculus is roughly triangular in shape, with an anterior-medial, anterior-lateral, and posterior surface. The latter presents some large-size pits on restricted lateral and median areas of the proximal funiculus, and several smaller-size ones close to the pedicel-funiculus joint. The entire surface of the antennal sub-segment appears densely populated by microtrichia and is inhabited by seven types of sensilla: one trichoid, two basiconic, one auriculate, one coeloconic, and two basiconic-like pit sensilla. Trichoid, basiconic, auriculate and basiconic-like types display a multiporous wall, a feature characteristic of insect olfactory sensilla. It remains to be verified whether or not the coeloconic structure type has wall pores. The most abundant sensilla are the trichoid ones, which are followed by the basiconic, coeloconic and auriculate types in a decreasing density order. The basiconic-like pit sensilla are present only on the posterior funicular surface, unlike the remaining ones which populate the entire sub-segment. The blow fly' funiculus displays a significant, even though moderate sexual dimorphism, the female sub-segment being bigger and presenting a higher number of trichoid and auriculate sensilla. The presence of multiple wall pores in most of sensilla types implies an olfactory modality for sensory neurons they accomodate, thus indicating that the blow fly' funiculus is a plain olfactory organ., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Olfactory sensory stimulation induces a fast-phase arrest response (FPA-R) of the blowfly heart activity that has been described as a sensitive tool for testing insect reactivity to odor perception. We analyzed FPA-R occurrence to repeated olfactory stimulation with low and high 1-hexanol concentrations that are behaviorally attractant and repellent, respectively, in the blowfly. FPA-R occurrence diminished and ceased with repeated presentations of low and medium odor concentrations, according to dynamics inversely related to odor doses. On the other hand, repeated stimulation with higher odor concentrations induced persistent FPA-Rs. Sensory input amplitude to repeated presentations of singly tested odor concentrations did not change throughout stimulation sessions. A spontaneous restoration of FPA-R to olfactory stimulation was recorded 30 min after cessation of FPA-R to a previous olfactory stimulation session. However, a prompt restoration of FPA-R to olfactory stimulation after cessation of FPA-R was obtained following mechano-taste stimulation of labellar sensilla. Our findings show that the FPA-R habituates to olfactory sensory stimulation with low and medium odor concentrations according to dynamics inversely related to odor intensities. On the other hand, the FPA-R does not habituate to higher odor concentrations. Therefore, flies learn to disregard nonaversive odor information, but they cannot ignore iterative detection of a repellent volatile.

The subcellular heterogeneity of mitochondrial membrane potential (mDelta psi) was investigated in confluent and sub-confluent cultures of four cell types (human astrocytes, HEp-2, MDCK and Vero cells) in normal growth conditions, hypoxia and apoptosis. The distribution of high-polarized mitochondria, detected by the potential-sensitive probe JC-1, was found to depend on: (1) the proximity to the cell edge; (2) the local absence of cell-cell contacts; and (3) the local absence of acidic vesicles. Both hypoxia and apoptosis produced a general mDelta psi increase with different redistributions of high-polarized mitochondria. Hypoxic cells maintained high-polarized mitochondria for over 24 hours, until cells underwent necrosis. On the other hand, apoptotic cells showed an unexpected convergence of high-polarized mitochondria into an extremely packed mass at one side of the nucleus, in a stage preceding nuclear condensation, but correlated to the retraction of cell-cell contacts.

Centromeric alphoid DNAs of human chromosomes 6, 9, 16 and Y were employed to obtain information on the molecular mechanism(s) determining cytological effects produced by digestion in situ with AluI and TaqI restriction enzymes, possibly related to the structure of the above-cited areas. The following cytological and biochemical experiments were carried out using the above-mentioned alphoid sequences as probes: (1) standard in-situ hybridization and in-situ hybridization after chromosome cleavage with AluI/TaqI, and (2) filter hybridization on the DNA fractions obtained from the material solubilized and that retained on the slides after digestion in situ with AluI/TaqI. Biochemical data show that cleavage of alphoid DNAs is not prevented by the peculiar organization of centromeric heterochromatin, but such cleavage is not necessarily followed by complete DNA solubilization. The analysis of alphoid sequence cleavage in naked genomic DNA as well as during digestion of fixed chromosomes shows that (1) AluI cuts more efficiently than TaqI, (2) DNA fragments as large as 3-5 kb can be solubilized, and (3) DNA fragments of the same size are found in both fractions of DNA, i.e. that retained on the chromosomes as well as that solubilized from chromosomes. Cytological data show that previous chromosome digestion, mostly with TaqI, increases the hybridization signal area, suggesting that this fact might be due to (1) chromatin reorganization produced by enzyme attack and/or (2) the presence of alphoid DNAs which might be restricted not only to the kinetochore area but also to para/peri-centromeric heterochromatin. Lastly, centromere DNA solubilization as a consequence of restriction enzyme cleavage seems to vary from chromosome to chromosome, thus suggesting that centromeric regions do not represent a homogeneous class of constitutive heterochromatin.

Many cytological processes such as cell proliferation, differentiation, transformation, apoptosis, etc., are accompanied by specific chromatin changes, usually identified on the basis of the relative content of euchromatin and heterochromatin. In order to achieve a quantitative, non-subjective evaluation of the chromatin pattern, two different approaches may be undertaken, one consisting in the analysis of the several morphological features of chromatin grains (size, shape, density, arrangement, and distribution), and the second consisting in the analysis of the chromatin globally considered as a coherent texture. Although the second approach appears to be simpler and more suitable, methods of texture analysis--including those specifically designed for the analysis of the chromatin pattern--are rarely applied due mainly to the unsuitability of sampling procedures and the excessive crypticism of results. As an alternative to traditional texture analysis, we suggest a method supported by a sound mathematical theory and approximately 30 years of applications in the field of geostatistics. The method, called variogram, analyzes the intrinsic structure of data sampled at different distance intervals and directions, and outputs easily understandable results. Recently, variogram analysis has successfully been exported from geostatistics to other fields (for example, ecology and epidemiology) that make use of spatially referenced variables. Based on the fact that pixels represent a perfect array of data ordered at regular distance intervals and directions, the variogram can be adopted to explore nuclear images and recognize chromatin patterns. Variograms of different nuclei can be summarized by multivariate methods without the need of previous standardization of data. This allows comparison and discrimination of chromatin patterns from mixed cell populations. Preliminary data obtained from young neurons undergoing massive apoptosis reveal a self-consistent map of nuclear changes correlated to the degenerative process.

The immunohistochemical occurrence of trkA, trkB and trkC receptors was examined in the human trigeminal ganglion and spinal nucleus of subjects at all ages and compared with that of substance P (SP) and calcitonin gene-related peptide (CGRP), trk-like immunoreactive (LI) material was detectable in discrete subpopulations of primary sensory neurones from 25 weeks of gestation to adult life. Each subpopulation overlapped partially with those immunoreactive to SP and CGRP, trkA- and trkC-positive filamentous and punctate elements occurred in the trigeminal subnucleus caudalis. While immunostaining for trkC was restricted to rare isolated elements, that for trkA outlined the superficial laminae of the nucleus and was more intense early in life than in adults.

The present paper describes a simple procedure for the analysis of chromatin texture. High-resolution digitized images of nuclei are first standardized to render gray values invariant to staining and illumination conditions. Subsequently, the nucleus is subdivided by a square grid into 0.4 x 0.4 microns2 quadrats and standard deviations of gray values within each quadrat are estimated. Finally, the overall mean and standard deviation of quadrat standard deviations are calculated. These values may be considered as pure descriptors of the nuclear texture, as they represent the distribution of chromatin changes, disregarding any absolute densitometric and morphometric feature. Using the above descriptors it is possible to recognize at least seven chromatin patterns in a mixed population of developing and degenerating neurons. Results are visually verified by mapping the original pictures at the corresponding bivariate plot points. Comparison with the Markovian texture analysis is discussed.

Immunohistochemistry was used to examine the occurrence and colocalization of the growth-associated protein GAP-43 with substance P (SP) and calcitonin gene-related peptide (CGRP) in the human trigeminal ganglion and sensory nucleus at perinatal and adult life stages. The results obtained show that: GAP-43-like immunoreactive (LI) material persists in trigeminal primary sensory neurones of the normal adult; the GAP-43-LI ganglionic population partially overlaps with those immunoreactive to SP and CGRP; the distribution pattern of the protein in the spinal nucleus varies with age; in the adult subnucleus caudalis GAP-43 is co-distributed with SP and CGRP. It is suggested that the trigeminal GAP-43-LI neuronal system may retain the capacity for structural and functional plasticity in adult life.