Iron overload during the embryonic period develops hyperactive like behavior and dysregulation of biogenic amines in Drosophila melanogaster.

Iron (Fe) is used in various cellular functions, and a constant balance between its uptake, transport, storage, and use is necessary to maintain its homeostasis in the body. Changes in Fe metabolism with a consequent overload of this metal are related to neurological changes and cover a broad spectrum of diseases, mainly when these changes occur during the embryonic period. This work aimed to evaluate the effect of exposure to Fe overload during the embryonic period of Drosophila melanogaster. Progenitor flies (male and female) were exposed to ferrous sulfate (FeSO4) for ten days in concentrations of 0.5, 1, and 5 â€‹mM. After mating and oviposition, the progenitors were removed and the treatment bottles preserved, and the number of daily hatches and cumulative hatching of the first filial generation (F1) were counted. Subsequently, F1 flies (separated by sex) were subjected to behavioral tests such as negative geotaxis test, open field test, grooming, and aggression test. They have evaluated the levels of dopamine (DA), serotonin (5-HT), octopamine (OA), tryptophan and tyrosine hydroxylase (TH), acetylcholinesterase, reactive species, and the levels of Fe in the progenitor flies and F1. The Fe levels of F1 flies are directly proportional to what is incorporated during the period of embryonic development; we also observed a delay in hatching and a reduction in the number of the hatch of F1 flies exposed during the embryonic period to the 5mM Fe diet, a fact that may be related to the reduction of the cell viability of the ovarian tissue of progenitor flies. The flies exposed to Fe (1 and 5 â€‹mM) showed an increase in locomotor activity (hyperactivity) and a significantly higher number of repetitive movements. In addition to a high number of aggressive encounters when compared to control flies. We can also observe an increase in the levels of biogenic amines DA and 5-HT and an increase in TH activity in flies exposed to Fe (1 and 5 â€‹mM) compared to the control group. We conclude that the hyperactive-like behavior demonstrated in both sexes by F1 flies exposed to Fe may be associated with a dysregulation in the levels of DA and 5-HT since Fe is a cofactor of TH, which had its activity increased in this study. Therefore, more attention is needed during the embryonic development period for exposure to Fe overload.

Hormone-mediated modulation of the electromotor CPG in pulse-type weakly electric fish. Commonalities and differences across species.

Like stomatogastric activity in crustaceans, vocalization in teleosts and frogs, and locomotion in mammals, the electric organ discharge (EOD) of weakly electric fish is a rhythmic and stereotyped electromotor pattern. The EOD, which functions in both perception and communication, is controlled by a two-layered central pattern generator (CPG), the electromotor CPG, which modifies its basal output in response to environmental and social challenges. Despite major anatomo-functional commonalities in the electromotor CPG across electric fish species, we show that Gymnotus omarorum and Brachyhypopomus gauderio have evolved divergent neural processes to transiently modify the CPG outputs through descending fast neurotransmitter inputs to generate communication signals. We also present two examples of electric behavioral displays in which it is possible to separately analyze the effects of neuropeptides (mid-term modulation) and gonadal steroid hormones (long-term modulation) upon the CPG. First, the nonbreeding territorial aggression of G. omarorum has been an advantageous model to analyze the status-dependent modulation of the excitability of CPG neuronal components by vasotocin. Second, the seasonal and sexually dimorphic courtship signals of B. gauderio have been useful to understand the effects of sex steroids on the responses to glutamatergic inputs in the CPG. Overall, the electromotor CPG functions in a regime that safeguards the EOD waveform. However, prepacemaker influences and hormonal modulation enable an enormous versatility and allows the EOD to adapt its functional state in a species-, sex-, and social context-specific manners.

Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila.

The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila.

Involvement of bradykinin, cytokines, sympathetic amines and prostaglandins in formalin-induced orofacial nociception in rats.

1. This study characterises some of the mechanisms and mediators involved in the orofacial nociception triggered by injection of formalin into the upper lip of the rat, by assessing the influence of various treatments on behavioural nociceptive responses (duration of facial rubbing) elicited either by a low subthreshold (i.e. non-nociceptive; 0.63%) or a higher concentration of the algogen (2.5%). 2. The kininase II inhibitor captopril (5 mg kg(-1), s.c.) and prostaglandin(PG) E(2) (100 ng lip(-1)) potentiated both phases of the response to 0.63% formalin, whereas tumour necrosis factor (TNF alpha; 5 pg lip(-1)), interleukin(IL)-1 beta (0.5 pg lip(-1)), IL-6 (2 ng lip(-1)) and IL-8 (200 pg lip(-1)), or the indirectly acting sympathomimetic drug tyramine (200 microg lip(-1)), each augmented only the second phase of nociception. 3. Conversely, both phases of nociception induced by 2.5% formalin were inhibited by the bradykinin (BK) B(2) receptor antagonist HOE140 (5 microg lip(-1)) or the selective beta(1)-adrenoceptor antagonist atenolol (100 microg lip(-1)). However, the BK B(1) receptor antagonist des-Arg(9)-Leu(8)-BK (1 and 2 microg lip(-1)), antibody and/or antiserum against each of the cytokines, the adrenergic neurone blocker guanethidine (30 mg kg(-1) day(-1), s.c., for 3 days) and the cyclooxygenase(COX)-2 inhibitor celecoxib (50 and 200 microg lip(-1), s.c.; or 1 and 3 mg kg(-1), i.p.) reduced only the second phase of the response. The nonselective COX inhibitor indomethacin and the 5-lipoxygenase activating protein inhibitor MK886 did not change formalin-induced nociception. 4. Our results indicate that BK, TNF-alpha, IL-1 beta, IL-6, IL-8, sympathetic amines and PGs (but not leukotrienes) contribute significantly to formalin-induced orofacial nociception in the rat and the response seems to be more susceptible to inhibition by B(2) receptor antagonist and selective COX-2 inhibitor than by B(1) receptor antagonist or nonselective COX inhibitor.

¿Existe una relación entre la depresión y la hipertension? / Is there a relationship between depression and hypertension?

La depresión es presentada en los pacientes hipertensos, con más frecuencia que en la población general. Los autores revisan las 4 hipótesis propuestas para explicar esta asociación y encuentran que la posibilidad de una relación etiológica entre las dos enfermedades es una hipótesis interesante pero que no está confirmada. En cambio la depresión puede ser un efecto secundario de ciertas drogas antihipertensoras que agotan las aminas cerebrales y, en otros casos puede ser una reaccióm psicológica contra una enfermedad crónica

Microiontophoresis of biogenic amines on cortical neurons: amounts of NA, DA and 5-HT ejected, compared with tissue content.

The present series of studies were carried out to quantify the amounts of dopamine (DA), noradrenaline (NA) and serotonin (5-HT) ejected from iontophoresis micropipettes and that produce inhibitory and modulatory effects on cortical neurons, in the frontoparietal cortex of the rat and in the occipital cortex of the cat. Using radioactive isotopes of the biogenic amines the effective transport number (n) was found to be 0.08 for DA; 0.13 for NA, and 0.22 for 5-HT. In addition, similar determinations were made, for comparison purposes, of the transport numbers of the neurotransmitters acetylcholine (ACh; n = 0.44), gamma-amino-n-butyrate (GABA, n = 13), and glutamate (GLU; n = 0.27). The quantities ejected under in vivo conditions were then estimated using Faraday's formula and fell in the pmol range (10(-12) mol). The effects of DA, NA and 5-HT on cortical units were studied; the amounts ejected were compared with the endogenous tissue content of these amines, determined by means of specific and sensitive radioenzymatic assays in the regions where the microiontophoretic experiments were performed. These results are discussed in the light of the anatomical, biochemical and electrophysiological data suggesting a modulatory role for the biogenic amines in the cerebral neocortex.