A thalamo-preoptic pathway promoting social touch

Social touch is an important form of communication, it is still unknown how it is processed. Here, we discovered a functional role for a neuronal pathway projecting from the posterior intralaminar thalamic nucleus (PIL) to the medial preoptic area (MPOA) in controlling social contact. Neurons in the PIL and the MPOA were activated by physical contact between female rodents and also by chemogenetic stimulation of PIL neurons. Chemogenetic stimulation of PIL neurons tagged by social contact experience increased direct physical interactions between familiar female rats without affecting other forms of social behavior. Furthermore, selective stimulation of the PIL-MPOA pathway, and the local activation of PIL terminals within the MPOA, elevated direct social contact between the animals suggesting the role of pathway-specific activated cell assemblies. Neurons projecting from the PIL to the MPOA contain the neuropeptide parathyroid hormone 2 (PTH2). The expression of the peptide was induced by social housing, the presence of PTH2 receptor was identified in MPOA neurons, and local injection of PTH2 increased the firing rate of identified preoptic area GABAergic neurons via the PTH2 receptor suggesting that PTH2 acts as a neurotransmitter in the PIL-MPOA pathway. We also found a homologous PIL to MPOA neuronal pathway in the human brain. Altogether, we discovered a direct thalamo-preoptic pathway, which bypasses the cerebral cortex and controls social touch. This pathway originates in neurons expressing PTH2, a neuropeptide recently shown in fish to respond to the social environment. These observations provide evidence for common evolutionary-conserved PTH2-containing social-touch specific engram circuits.

Hypothalamic regulation of reproduction under the chronic influence of toluene and melatonin

Experiments on chronic administration of melatonin with and without chronic inhalation of toluene dosed at both maximal permissible concentration (50 mg/ml) and limited chronical range (500 mg/m3) have been carried out on female rats to discover their effects on biogenic amines system in hypothalamic structures related to gonadoliberin synthesis and secretion - preoptic area (PA) and median eminence (ME). Contents of biogenic amines in ME and especially in PA have been shown to have circadian variations with maximum in the morning in control group of rats.The chronic effect of synchronizing agent melatonin (administered dissolved in drinking water in concentration of 10 pg/m l, at night during 2 months) on neotransmitters and their circadian variations in both hypothalamic structures proved surprisingly to be much alike the effect of toluene. Both chemicals cause the disturbances of normal circadian variations o f norepinephrine, dopamine and serotonine in PA and dopamine in ME. The simultaneous administration of toluene and melatonin showed likewise no synchronizing ability of the latter under the conditions described.

Erectile Function and Sexual Behavior: A Review of the Role of Nitric Oxide in the Central Nervous System

Nitric oxide (NO), the neuromodulator/neurotransmitter formed from l-arginine by neuronal, endothelial and inducible NO synthases, is involved in numerous functions across the body, from the control of arterial blood pressure to penile erection, and at central level from energy homeostasis regulation to memory, learning and sexual behavior. The aim of this work is to review earlier studies showing that NO plays a role in erectile function and sexual behavior in the hypothalamus and its paraventricular nucleus and the medial preoptic area, and integrate these findings with those of recent studies on this matter. This revisitation shows that NO influences erectile function and sexual behavior in males and females by acting not only in the paraventricular nucleus and medial preoptic area but also in extrahypothalamic brain areas, often with different mechanisms. Most importantly, since these areas are strictly interconnected with the paraventricular nucleus and medial preoptic area, send to and receive neural projections from the spinal cord, in which sexual communication between brain and genital apparatus takes place, this review reveals that central NO participates in concert with neurotransmitters/neuropeptides to a neural circuit controlling both the consummatory (penile erection, copulation, lordosis) and appetitive components (sexual motivation, arousal, reward) of sexual behavior.

A temperature-regulated circuit for feeding behavior

Both rodents and primates have evolved to orchestrate food intake to maintain thermal homeostasis in coping with ambient temperature challenges. However, the mechanisms underlying temperature-coordinated feeding behavior are rarely reported. Here we found that a non-canonical feeding center, the anteroventral and periventricular portions of medial preoptic area (apMPOA) responded to altered dietary states. Two neighboring but distinct apMPOA neurons mediated feeding in receiving anatomical inputs from external and dorsal subnuclei of lateral parabrachial nucleus (LPB). While both populations are glutamatergic, the arcuate nucleus (ARC)-projecting neurons in apMPOA can sense low temperature and promote food intake. The other type, the paraventricular hypothalamic nucleus (PVH)-projecting neurons in apMPOA are primarily sensitive to high temperature and suppress food intake. Cutting off both pathways can eliminate the temperature-dependence of feeding. Further projection-specific RNA sequencing identified that the two neuronal populations were molecularly marked by galanin receptor and apelin receptor. These findings reveal an unrecognized cell populations and circuits of apMPOA that orchestrates feeding behavior against thermal challenges.

Autoradiographic localization of [3H]-Nisoxetine binding sites in the CNS of male and female Japanese quail

Background In the central nervous system of mammals, transporters localized on the presynaptic nerve terminals regulate the reuptake of neurotransmitters. These transporters are selective for a specific neurotransmitter such as dopamine (DA) and norepinephrine (NE). Specifically in the synapse, the dopamine transporter (DAT) reuptakes DA and the norepinephrine transporter (NET) reuptakes NE. However previous research has found that avian species do not have a gene for DAT, and therefore, birds may be using the NET to clear both NE and DA from the synapse. The current study aimed to extend this finding by localizing NET expression in male and female Japanese quail (Coturnix japonica) brains using [3H]Nisoxetine, a selective NET blocker. Results High densities of binding sites were observed in the olfactory tubercle (OTu), the medial striatum (MSt), and the lateral striatum (LSt). Lower densities of binding sites were detected in the amygdala (AMY) and hypothalamus (Hyp), and low binding was found in the medial preoptic area (mPOA) and the pallium. Conclusion The areas with the highest densities of NET are also areas that previous research has shown to have high levels of DA activity but low levels of NE innervation (e.g. striatum). The distribution of this reuptake transporter is consistent with the theory that NET acts to clear both DA and NE from the synapse.

A reduction in voluntary physical activity in early pregnancy in mice is mediated by prolactin

As part of the maternal adaptations to pregnancy, mice show a rapid, profound reduction in voluntary running wheel activity (RWA) as soon as pregnancy is achieved. Here, we evaluate the hypothesis that prolactin, one of the first hormones to change secretion pattern following mating, is involved in driving this suppression of physical activity levels during pregnancy. We show that prolactin can acutely suppress RWA in non-pregnant female mice, and that conditional deletion of prolactin receptors (Prlr) from either most forebrain neurons or from GABA neurons prevented the early pregnancy-induced suppression of RWA. Deletion of Prlr specifically from the medial preoptic area, a brain region associated with multiple homeostatic and behavioural roles including parental behaviour, completely abolished the early pregnancy-induced suppression of RWA. As pregnancy progresses, prolactin action continues to contribute to the further suppression of RWA, although it is not the only factor involved. Our data demonstrate a key role for prolactin in suppressing voluntary physical activity during early pregnancy, highlighting a novel biological basis for reduced physical activity in pregnancy.