The restructuring of muscarinic receptor subtype gene transcripts in c-fos knock-out mice

Mapping of the prenatal and postnatal methamphetamine effects on D1-like dopamine, M1 and M2 muscarinic receptors in rat central nervous system

Methamphetamine (MA) is worldwide known drug with high potential for addiction that causes dopamine, noradrenaline and serotonin release. MA is also able to increase acetylcholine levels in adult rodents. The aim of this study was to map changes in D₁-like dopamine receptors (DR), M₁ and M₂ muscarinic receptors (MR), and the total number of MR (M₁-M₅ MR) in the CNS of rats exposed to MA prenatally and in adulthood. Rat mothers were exposed to MA (5mg/kg s.c.) or saline during the entire gestation period and their male offspring were administered in adulthood with single MA (1mg/kg) or saline injection. Thus, the animals were divided into 4 groups: prenatally MA-exposed rats treated with saline (MA/S) or MA (MA/MA) in adulthood and prenatally saline-exposed rats treated with saline (S/S) or MA (S/MA) in adulthood. One hour after the acute treatment animals were sacrificed and their brains were removed. The numbers of M₁, M₂, total MR, and D₁-DR were measured by autoradiography. The main effect was detected in the hippocampus with the most affected M₁ MR. D₁-DR were decreased in motor cortex and substantia nigra. M₁MR were decreased in caudate-putamen, dorsal hippocampus, CA1, CA3 and dentate gyrus (DG). M₂MR were decreased in DG only. Total number of MR was moreover decreased in dorsal hippocampus, CA1, CA3 and DG. Our results have shown different patterns of changes in DR and MR, suggesting a pilot role of M₁ MR in the CNS changes induced by prenatal and adult MA exposure.

Gonadotropin and kisspeptin gene expression, but not GnRH, are impaired in cFOS deficient mice

cFOS is a pleiotropic transcription factor, which binds to the AP1 site in the promoter of target genes. In the pituitary gonadotropes, cFOS mediates induction of FSHβ and GnRH receptor genes. Herein, we analyzed reproductive function in the cFOS-deficient mice to determine its role in vivo. In the pituitary cFOS is necessary for gonadotropin subunit expression, while TSHβ is unaffected. Additionally, cFOS null animals have the same sex-steroid levels, although gametogenesis is impeded. In the brain, cFOS is not necessary for GnRH neuronal migration, axon targeting, cell number, or mRNA levels. Conversely, cFOS nulls, particularly females, have decreased Kiss1 neuron numbers and lower Kiss1 mRNA levels. Collectively, our novel findings suggest that cFOS plays a cell-specific role at multiple levels of the hypothalamic-pituitary-gonadal axis, affecting gonadotropes but not thyrotropes in the pituitary, and kisspeptin neurons but not GnRH neurons in the hypothalamus, thereby contributing to the overall control of reproduction.

Elevated Hippocampal Cholinergic Neurostimulating Peptide precursor protein (HCNP-pp) mRNA in the amygdala in major depression

The amygdala is innervated by the cholinergic system and is involved in major depressive disorder (MDD). Evidence suggests a hyper-activate cholinergic system in MDD. Hippocampal Cholinergic Neurostimulating Peptide (HCNP) regulates acetylcholine synthesis. The aim of the present work was to investigate expression levels of HCNP-precursor protein (HCNP-pp) mRNA and other cholinergic-related genes in the postmortem amygdala of MDD patients and matched controls (females: N = 16 pairs; males: N = 12 pairs), and in the mouse unpredictable chronic mild stress (UCMS) model that induced elevated anxiety-/depressive-like behaviors (females: N = 6 pairs; males: N = 6 pairs). Results indicate an up-regulation of HCNP-pp mRNA in the amygdala of women with MDD (p < 0.0001), but not males, and of UCMS-exposed mice (males and females; p = 0.037). HCNP-pp protein levels were investigated in the human female cohort, but no difference was found. There were no differences in gene expression of acetylcholinesterase (AChE), muscarinic (mAChRs) or nicotinic receptors (nAChRs) between MDD subjects and controls or UCMS and control mice, except for an up-regulation of AChE in UCMS-exposed mice (males and females; p = 0.044). Exploratory analyses revealed a baseline expression difference of cholinergic signaling-related genes between women and men (p < 0.0001). In conclusion, elevated amygdala HCNP-pp expression may contribute to mechanisms of MDD in women, potentially independently from regulating the cholinergic system. The differential expression of genes between women and men could also contribute to the increased vulnerability of females to develop MDD.

Muscarinic receptor subtype mRNA expression in the human prostate: association with age, pathological diagnosis, prostate size, or potentially interfering medications?

As the prostate abundantly expresses muscarinic receptors and antagonists for such receptors are increasingly used in the treatment of men with voiding function and large prostates, we have explored an association of the mRNA expression of human M1, M2, M3, M4, and M5 receptors in human prostate with patient age, prostate size, prostate-specific antigen level, pathological diagnosis, and concomitant medication. mRNA was isolated from prostate chips of 110 consecutive patients undergoing transurethral resection of the prostate for the treatment of benign prostatic hyperplasia or prostate cancer. Expression of each of the five muscarinic receptor subtype transcripts was assessed by real-time PCR and association with patient age, prostate size, prostate-specific antigen level, pathological diagnosis, and concomitant medication were explored. M1 and M4 receptors were the most and least prevalently expressed subtypes in the human prostate, respectively. M1 receptor mRNA expression was weakly but significantly associated with prostate size (r = 0.2494, p = 0.0451), but mRNA expression of none of the five subtypes was significantly associated with age, prostate-specific antigen level, pathological diagnosis (benign prostatic hyperplasia vs. prostate cancer), or concomitant medication (5α-reductase inhibitors, α1- or β-adrenoceptor antagonists). We conclude that human prostate muscarinic receptor subtype transcripts apparently undergo only a very limited regulation by a variety of physiological, pathophysiological, or treatment factors. In light of the growing use of muscarinic receptor antagonists in men with voiding dysfunction including those with large prostates, the functional role of the weak association between M1 receptor mRNA expression and prostate size merits further investigation.