PACAP key interactions with PAC1, VPAC1, and VPAC2 identified by molecular dynamics simulations.

The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) belongs to the glucagon/secretin family. PACAP interacts with the pituitary adenylate cyclase-activating polypeptide receptor type 1 (PAC1) and vasoactive intestinal peptide receptors 1 and 2 (VPAC1 and VPAC2), exhibiting functions in the immune, endocrine, and nervous systems. This peptide is upregulated in numerous instances of brain injury, acting as a neuroprotective agent. It can also suppress HIV-1 and SARS-CoV-2 viral replication in vitro. This work aimed to identify, in each peptide-receptor system, the most relevant residues for complex stability and interaction energy communication via Molecular Dynamics (MD), Free Energy calculations, and Protein-energy networks, thus revealing in detail the underlying mechanisms of activation of these receptors. Hydrogen bond formation, interaction energies, and computational alanine scanning between PACAP and its receptors showed that His1, Asp3, Arg12, Arg14, and Lys15 are crucial to the peptide's stability. Furthermore, several PACAP interactions with structurally conserved positions deemed necessary in GPCR B1 activation, including Arg2.60, Lys2.67, and Glu7.42, were significant for the peptide's stability within the receptors. According to the protein-energy network, the connection between Asp3 of PACAP and the receptors' conserved Arg2.60 represents a critical energy communication hub in all complexes. Additionally, the ECDs of the receptors were also found to function as energy communication hubs for PACAP. Although the overall binding mode of PACAP in the three receptors was found to be highly conserved, Arg12 and Tyr13 of PACAP were more prominent in complex with PAC1, while Ser2 of PACAP was with VPAC2. The detailed analyses performed in this work pave the way for using PACAP and its receptors as therapeutic targets.Communicated by Ramaswamy H. Sarma.

The Rat Mammary Gland as a Novel Site of Expression of Melanin-Concentrating Hormone Receptor 1 mRNA and Its Protein Immunoreactivity.

Lactation is a complex physiological process, depending on orchestrated central and peripheral events, including substantial brain plasticity. Among these events is a novel expression of pro-melanin-concentrating hormone (Pmch) mRNA in the rodent hypothalamus, such as the ventral part of the medial preoptic area (vmMPOA). This expression reaches its highest levels around postpartum day 19 (PPD19), when dams transition from lactation to the weaning period. The appearance of this lactation-related Pmch expression occurs simultaneously with the presence of one of the Pmch products, melanin-concentrating hormone (MCH), in the serum. Given the relevance of the MPOA to maternal physiology and the contemporaneity between Pmch expression in this structure and the weaning period, we hypothesized that MCH has a role in the termination of lactation, acting as a mediator between central and peripheral changes. To test this, we investigated the presence of the MCH receptor 1 (MCHR1) and its gene expression in the mammary gland of female rats in different stages of the reproductive cycle. To that end, in situ hybridization, RT-PCR, RT-qPCR, nucleotide sequencing, immunohistochemistry, and Western blotting were employed. Although Mchr1 expression was detected in the epidermis and dermis of both diestrus and lactating rats, parenchymal expression was exclusively found in the functional mammary gland of lactating rats. The expression of Mchr1 mRNA oscillated through the lactation period and reached its maximum in PPD19 dams. Presence of MCHR1 was confirmed with immunohistochemistry with preferential location of MCHR1 immunoreactive cells in the alveolar secretory cells. As was the case for gene expression, the MCHR1 protein levels were significantly higher in PPD19 than in other groups. Our data demonstrate the presence of an anatomical basis for the participation of MCH peptidergic system on the control of lactation through the mammary gland, suggesting that MCH could modulate a prolactation action in early postpartum days and the opposite role at the end of the lactation.

Melanin-concentrating hormone (MCH) in the median raphe nucleus: Fibers, receptors and cellular effects.

Serotonergic neurons of the median raphe nucleus (MnR) and hypothalamic melanin-concentrating hormone (MCH)-containing neurons, have been involved in the control of REM sleep and mood. In the present study, we examined in rats and cats the anatomical relationship between MCH-containing fibers and MnR neurons, as well as the presence of MCHergic receptors in these neurons. In addition, by means of in vivo unit recording in urethane anesthetized rats, we determined the effects of MCH in MnR neuronal firing. Our results showed that MCH-containing fibers were present in the central and paracentral regions of the MnR. MCHergic fibers were in close apposition to serotonergic and non-serotonergic neurons. By means of an indirect approach, we also analyzed the presence of MCHergic receptors within the MnR. Accordingly, we microinjected MCH conjugated with the fluorophore rhodamine (R-MCH) into the lateral ventricle. R-MCH was internalized into serotonergic and non-serotonergic MnR neurons; some of these neurons were GABAergic. Furthermore, we determined that intracerebroventricular administration of MCH induced a significant decrease in the firing rate of 53 % of MnR neurons, while the juxtacellular administration of MCH reduced the frequency of discharge in 67 % of these neurons. Finally, the juxtacellular administration of the MCH-receptor antagonist ATC-0175 produced an increase in the firing rate in 78 % of MnR neurons. Hence, MCH produces a strong regulation of MnR neuronal activity. We hypothesize that MCHergic modulation of the MnR neuronal activity may be involved in the promotion of REM sleep and in the pathophysiology of depressive disorders.

Cloning, phylogenetic analysis and expression of somatolactin and its receptor in Cichlasoma dimerus: their role in long-term background color acclimation.

Somatolactin (SL) and SL receptor (SLR) belong to the growth hormone and cytokine type I receptor superfamilies, respectively. However, further research is required to define the duplications and functions of SL and its receptors in basal vertebrates including environmental background color adaptation in fish. In the present study, we cloned and sequenced SL and its putative receptor (SLR), classified and compared the sequences phylogenetically, and determined SL and SLR mRNA expression levels during long-term background color exposure in Cichlasoma dimerus, a freshwater South American cichlid. Our results show that C. dimerus SL and SLR share high sequence similarity with homologous from other perciform fish. Phylogenetic analysis indicates that C. dimerus SL belongs to the SLα clade sub-group. C. dimerus SLR is clearly a member of the GHR1 receptor subgroup, which includes the experimentally validated SLR from salmonids. Higher transcript levels of SLα in the pituitary and SLR in the epidermis and dermis cells of fish scales were observed in fish following long-term black background color exposure compared to those exposed to a white background. A higher number of melanophores was also observed in fish exposed for 10days to a black background compared to those exposed to a white background. These changes were concomitant to differences in SL or SLR transcript levels found in fish exposed to these two different background colors. Our results suggest, for the first time, that SLR is expressed in fish scales, and that there is an increase in SL in the pituitary and the putative SLR in likely target cells, i.e., melanophores, in long-term black background exposure in C. dimerus.

Ayurvedic genomics, constitutional psychology, and endocrinology: the missing connection.

A recent methodological approach for human classification, diagnosis, and therapeutics through the combination of current Western constitutional psychology somatotypes and traditional Indian medicine (prakriti) body types and mind (manas) is herein presented. The striking similarities between psychologic somatotypes and Indian medicine body types permits proposal of a finite genopsycho-somatotyping of humans. Genopsycho-somatotyping of humans consists of a set of common physiologic, physical, and psychologic attributes related to a common basic birth constitution that remains somewhat permanent during human lifetime, since it is proposed that this birth constitution is programmed in the person's DNA (genes). This mainly provides a tool for classifying the human population based on broad and finite phenotype clusters across different ethnicity, languages, geographical location, or self-reported ancestry. In spite of any social or environmental traumatic event, I propose for males that every basic constitution has an associated identification organ, a measured property or marker, a soma, and some psyche general tendencies suggesting specific behavior or recurrent conduct. Three (3) basic extreme genopsycho-somatotypes or birth constitutions are enunciated: mesomorphic or andrus (Pitta), endomorphic or thymus (Khapa), and ectomorphic or thyrus (Vata). The method further predicts that male andrus constitution across races shares similarities in androgen (An) nuclear receptor behavior, whereas thymus constitutions are mainly regulated by T-cells (Tc) nuclear receptor behavior. Moreover, it suggests that thyrus constitutions share similarities in thyroxine (Th) nuclear receptor behavior. These proposed nuclear receptors are expected to regulate the expression of specific genes, thereby controlling the embryonic development, adult homeostasis, and metabolism of the human organism in a very profound way. The method finally predicts small differences in measured property (An, Tc, and Th nuclear receptors behavior) within a birth constitution across different races to be expected by modulation effects in melanocyte-stimulating hormone receptor behavior.

Three-dimensional quantitative structure-activity relationship CoMSIA/CoMFA and LeapFrog studies on novel series of bicyclo [4.1.0] heptanes derivatives as melanin-concentrating hormone receptor R1 antagonists.

Comparative molecular similarity indices analysis (CoMSIA) and comparative molecular field analysis (CoMFA) were performed on a series of bicyclo [4.1.0] heptanes derivatives as melanin-concentrating hormone receptor R1 antagonists (MCHR1 antagonists). Molecular superimposition of antagonists on the template structure was performed by database alignment method. The statistically significant model was established on sixty five molecules, which were validated by a test set of ten molecules. The CoMSIA model yielded the best predictive model with a q(2) = 0.639, non cross-validated R(2) of 0.953, F value of 92.802, bootstrapped R(2) of 0.971, standard error of prediction = 0.402, and standard error of estimate = 0.146 while the CoMFA model yielded a q(2) = 0.680, non cross-validated R(2) of 0.922, F value of 114.351, bootstrapped R(2) of 0.925, standard error of prediction = 0.364, and standard error of estimate = 0.180. CoMFA analysis maps were employed for generating a pseudo cavity for LeapFrog calculation. The contour maps obtained from 3D-QSAR studies were appraised for activity trends for the molecules analyzed. The results show the variability of steric and electrostatic contributions that determine the activity of the MCHR1 antagonist, with these results we proposed new antagonists that may be more potent than previously reported, these novel antagonists were designed from the addition of highly electronegative groups in the substituent di(i-C(3)H(7))N- of the bicycle [4.1.0] heptanes, using the model CoMFA which also was used for the molecular design using the technique LeapFrog. The data generated from the present study will further help to design novel, potent, and selective MCHR1 antagonists.

Evaluación de la reserva pituitaria de TSH en recien nacidos normales de altura / Evaluation of TSH's pituitary reservation(reserve) in normal newborn children of height

Se investiga las concentraciones séricas de TSH de cordón umbilical y la respuesta de TSH a ka estimulación de TRH en 8 recién nacidos a término, de parto eutócico, nativos de la altura (4,300 m.s.n.m.) y un grupo control de 7 recién nacidos de nivel del mar, con similares características. El embarazo y el parto fueron normales, lo mismo que la excreción urinaria de yodo (EUI). Inmediatamente después del nacimiento, se administró TSH sintética por vía endovenosa a la dosis de 7 ug/kg y el TSH sérico fue deteminado a los 30, 120 y 180 minutos. En ambos grupos el TSH de cordón umbilical y el área de incremento de TSH fueron similares. Estos resultados favorecen la conclusión de que el recién nacido de la altura tiene una reserva pituitaria de TSH similar al de nivel del mar.

[Structural characteristics of prolactin, growth hormone and their receptors as determinants of biological actions]. / Características estructurales de la prolactina, la hormona de crecimiento, y sus receptores como determinantes de la acción biológica.

The pituitary hormones prolactin and growth hormone are structurally related. Both hormones exist in the circulation in several molecular forms, differing in aminoacid sequences, posttranslational modifications and fragments produced by proteolytic cleavage. Heterogencity may produce a diversity of inmunological and biological actions. It has been suggested that each of this forms may be a isohormone with a different physiological role. The predominance of one of them in serun could account for the complex and often contradictory actions of the hormones. In addition receptors also have structural homology and so the possibility exist that these hormones share binding affinity to the receptors and can produce endocrinological problems in some special conditions.

Características estructurales de la prolactina, la hormona de crecimiento, y sus receptores como determinantes de la acción biológica / Structural characteristics of prolactin, grow hormone and their receptors as determinants of biologic action

En esta revisión se presenta un panorama general de la relación estructural que guardan la prolactina, la hormona de crecimiento y sus receptores. La hipófisis produce entre otras hormonas polipeptídicas, la prolactina (PRL) y la hormona de crecimiento (GH) que están esctructuralmente relacionadas. Ambas hormonas existen en la circulación como una mezcla de formas moleculares que difieren en la secuencia de aminoácidos, por modificaciones postranscripcionales, postransduccionales o producidos por rupturas proteolíticas. La heterogeneidad puede producir una diversidad, de acciones biológicas e inmunológicas; se ha sugerido que cada una de estas formas pueda ser una isohormona con un papel fisiológico diferente. La predominancia de una de ellas en el suero puede modificar la actividad de las hormonas y determinan una acción biológica diferente. Sumando a esto que los receptores presentan homología estructural y la posibilidad de que estas hormonas compartan afinidad de unión a los receptores se explica, que en algunas condiciones especiales se produzcan problemas endocrinológicos

Oestrogens down-regulate type I but not type II adrenal corticoid receptors in rat anterior pituitary.

We have studied type I and type II adrenal cortical steroid receptors in the anterior (AL), intermediate (IL) and posterior (PL) lobes of the pituitary and in the hippocampus of ovariectomized-adrenalectomized female rats and in castrated-adrenalectomized male animals, with or without oestrogen treatment. Using [3H]dexamethasone as ligand and conditions suitable for determination of its binding to type I and type II receptors, we found that 4 or 15 days of oestrogen reduced type I receptors in AL by 50-60% without changes in IL, PL or hippocampus, or in type II sites in any of the four neuroendocrine tissues studied. This down-regulatory effect was seen only in female rats and no change was found for males. The reduction in type I sites in AL in oestrogenized female rats was confirmed by labelling type I sites with the synthetic antimineralocorticoid [3H]ZK 91587. Saturation analysis with [3H]ZK 91587 demonstrated that the reduction was due to a reduction in Bmax without change in Kd. We conclude that: (a) type I receptors in the anterior pituitary are under oestrogenic control; (b) there is a sex difference in the response to oestrogen of AL type I sites; and (c) this demonstration may be useful in determining the role of type I receptors in neuroendocrine regulation of the anterior pituitary by hormones derived from the adrenal cortex, and the participation of sex hormones in this process.