Preferential modulation of the lateral habenula activity by serotonin-2A rather than -2C receptors: Electrophysiological and neuroanatomical evidence

Aims: Serotonergic (5-HT) modulation of the lateral habenula (LHb) activity is central in normal and pathologic conditions such as mood disorders. Among the multiple 5-HT receptors (5-HTRs) involved, the 5-HT2CR seems to play a pivotal role. Yet, the role of 5-HT2ARs in the control of the LHb neuronal activity is completely unknown. Methods: Single-cell extracellular recording of the LHb neurons was used in rats to study the effect of the general activation and blockade of the 5-HT2CR and 5-HT2AR with Ro 60-0175 and SB242084, TCB-2 and MDL11939, respectively. The expression of both receptors in the LHb was confirmed using immunohistochemistry. Results: Cumulative doses (5-640 \uce\ubcg/kg, iv) of Ro 60-0175 and TCB-2 affected the activity of 34% and 63% of the LHb recorded neurons, respectively. LHb neurons were either inhibited at low doses or excited at higher doses of the 5-HT2A/CR agonists. SB242084 or MDL11939 (both at 200 \uce\ubcg/kg, iv) did not modify neuronal firing when injected alone, but reverted the bidirectional effects of Ro 60-0175 or TCB-2, respectively. 5-HT2CRs and 5-HT2ARs are expressed in less than the 20% of the LHb neurons, and they neither colocalize nor make heterodimers. Strikingly, only 5-HT2ARs are expressed by the majority of LHb astrocyte cells. Conclusions: Peripheral administration of 5-HT2AR agonist promotes a heterogeneous pattern of neuronal responses in the LHb, and these effects are more prominent than those induced by the 5-HT2CR activation

Distribution of α-transducin and α-gustducin immunoreactive cells in the chicken (Gallus domesticus) gastrointestinal tract

The expression and distribution patterns of the taste signaling molecules, α-gustducin (Gαgust) and α-transducin (Gαtran) G-protein subunits, were studied in the gastrointestinal tract of the chicken (Gallus domesticus) using the immunohistochemical method. Gαgust and Gαtran immunoreactive (-IR) cells were observed in the mucosal layer of all examined segments, except the esophagus, crop, and the saccus cranialis of the gizzard. The highest numbers of Gαgust and Gαtran-IR cells were found in the proventriculus glands and along the villi of the pyloric, duodenum, and rectal mucosa. Gαgust and Gαtran-IR cells located in the villi of the jejunum, ileum, and cloaca were much less numerous, while only a few Gαgust and Gαtran-IR cells were detected in the mucosa of the proventriculus and cecum. In the crypts, IR cells were observed in the small and large intestine as well as in the cloaca. Gαgust and Gαtran-IR cells displayed elongated ("bottle-" or "pear-like") or rounded shape. The demonstration of Gαgust and Gαtran expression provides evidence for taste receptor mediated mucosal chemosensitivity in the chicken gastrointestinal tract

The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study

The phase transition of the quantum spin-1/2 frustrated Heisenberg antiferroferromagnet on an anisotropic square lattice is studied by using a variational treatment. The model is described by the Heisenberg Hamiltonian with two antiferromagnetic interactions: nearest-neighbor (NN) with different coupling strengths J_{1} and J_{1'} along x and y directions competing with a next-nearest-neighbor coupling J_{2} (NNN). The ground state phase diagram in the ({\lambda},{\alpha}) space, where {\lambda}=J_{1'}/J_{1} and {\alpha}=J_{2}/J_{1}, is obtained. Depending on the values of {\lambda} and {\alpha}, we obtain three different states: antiferromagnetic (AF), collinear antiferromagnetic (CAF) and quantum paramagnetic (QP). For an intermediate region {\lambda}_{1}<{\lambda}<1 we observe a QP state between the ordered AF and CAF phases, which disappears for {\lambda} above some critical value {\lambda}_{1}. The boundaries between these ordered phases merge at the quantum critical endpoint (QCE). Below this QCE there is again a direct first-order transition between the AF and CAF phases, with a behavior approximately described by the classical line {\alpha}_{c}{\simeq}{\lambda}/2

Stroke management during the coronavirus disease 2019 (COVID-19) pandemic: experience from three regions of the north east of Italy (Veneto, Friuli-Venezia-Giulia, Trentino-Alto-Adige)

Background: Efficiency of care chain response and hospital reactivity were and are challenged for stroke acute care management during the pandemic period of coronavirus disease 2019 (COVID-19) in North-Eastern Italy (Veneto, Friuli-Venezia-Giulia, Trentino-Alto-Adige), counting 7,193,880 inhabitants (ISTAT), with consequences in acute treatment for patients with ischemic stroke. Methods: We conducted a retrospective data collection of patients admitted to stroke units eventually treated with thrombolysis and thrombectomy, ranging from January to May 2020 from the beginning to the end of the main first pandemic period of COVID-19 in Italy. The primary endpoint was the number of patients arriving to these stroke units, and secondary endpoints were the number of thrombolysis and/or thrombectomy. Chi-square analysis was used on all patients; furthermore, patients were divided into two cohorts (pre-lockdown and lockdown periods) and the Kruskal-Wallis test was used to test differences on admission and reperfusive therapies. Results: In total, 2536 patients were included in 22 centers. There was a significant decrease of admissions in April compared to January. Furthermore, we observed a significant decrease of thrombectomy during the lockdown period, while thrombolysis rate was unaffected in the same interval across all centers. Conclusions: Our study confirmed a decrease in admission rate of stroke patients in a large area of northern Italy during the lockdown period, especially during the first dramatic phase. Overall, there was no decrease in thrombolysis rate, confirming an effect of emergency care system for stroke patients. Instead, the significant decrease in thrombectomy rate during lockdown addresses some considerations of local and regional stroke networks during COVID-19 pandemic evolution

Expression of \u3b22 adrenoceptors within enteric neurons of the horse ileum

The activity of the gastrointestinal tract is regulated through the activation of adrenergic receptors (ARs). Since data concerning the distribution of ARs in the horse intestine is virtually absent, we investigated the distribution of \u3b22-AR in the horse ileum using double-immunofluorescence. The \u3b22-AR-immunoreactivity (IR) was observed in most (95%) neurons located in submucosal plexus (SMP) and in few (8%) neurons of the myenteric plexus (MP). Tyrosine hydroxylase (TH)-IR fibers were observed close to neurons expressing \u3b22-AR-IR. Since \u3b22-AR is virtually expressed in most neurons located in the horse SMP and in a lower percentage of neurons in the MP, it is reasonable to retain that this adrenergic receptor could regulate the activity of both secretomotor neurons and motor neurons innervating muscle layers and blood vessels. The high density of TH-IR fibers near \u3b22-AR-IR enteric neurons indicates that the excitability of these cells could be directly modulated by the sympathetic system

Proiezioni mesencefaliche dirette al midollo spinale lombo-sacrale nel bovino

The distribution and the morphology of the mesencephalic neurons projecting to the lumbo-sacral spinal cord levels was investigated with the fluorescent retrograde tracer technique in the cattle. The experiments utilised three male Fresian calves. Fast Blue (FB) was injected at L6-S1 spinal cord levels. After 7 weeks, the animals were sacrificed. The midbrain was removed, fixed, cut on a freezing microtome in serial transverse sections and observed with an epifluorescence microscope. Labelled neurons of the red nucleus, the interstitial nucleus of Cajal, the Edinger-Westphal nucleus, the periaqueductal grey and the mesencephalic reticular formation were counted. Morphometric analysis of labelled neurons was carried out. In the red nucleus we observed about 1500 labelled multipolar neurons, distributed caudo-rostrally along its length (7300 &#956;m). The cells showed a wide area range (430-6280 &#956;m2). FB labelled neurons belonging to the other nuclei were analyzed

A new method of producing casts for anatomical studies

The objective of the present study was to verify if polyurethane foam is a suitable material to make accurate casts of vessels and viscera, and to develop a method based on its use for anatomical studies. This new technique has been tested primarily on the lungs of different animals, but also on the renal, intestinal and equine digital vessels. It consisted of three steps: specimen preparation, injection of the foam and corrosion of the cast. All structures injected with foam were properly filled. The bronchial tree and the vessels could be observed up to their finer branches. The method is inexpensive, simple and requires no special equipment. The pre-casting procedure does not require perfusion of the specimens with formalin, or prolonged flushing with carbon dioxide gas or air for drying. The polyurethane foam does not need a catalyst. It is simply diluted with acetone, which does not cause shrinkage of the cast due to evaporation during hardening. The foam naturally expands into the cavities without high pressure of the inoculum, and hardens in just 2 or 3 h at room temperature. Only two drawbacks were observed. The first is the fact that multiple injections cannot be made in the same cavity since the foam solidifies quickly; the second is the slight brittleness of the cast, due to the low elasticity of polyurethane foam. In conclusion, polyurethane foam was a suitable material for producing accurate casts of vessels and viscera

Localization of the 5-hydroxytryptamine 4 receptor in equine enteric neurons and extrinsic sensory fibers

Background: Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5-HT4 exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5-HT4 agonists is well known, the cellular sites of 5-HT4 expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5-HT4 in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprung's disease. Methods: The intestine and spinal ganglia were obtained from three healthy horses and two foals with hereditary ileocolonic aganglionosis. Tissues were processed for immunohistochemistry using a specific antibody to 5-HT4 and a variety of neuronal markers. Myenteric and submucosal plexus 5-HT4-immunoreactive (IR) neurons were quantified as relative percentage (mean\ub1SD) to the total number of neurons counted. Furthermore, the density of 5-HT4-IR nerve fibers was evaluated in the mucosa and tunica muscularis. Key Results: The 5-HT4 immunoreactivity was localized to large percentages of myenteric neurons ranging from 28\ub19% (descending colon) to 63\ub119% (ileum), and submucosal neurons ranging from 54\ub16% (ileum) to 68\ub114% (duodenum). The 5-HT4-immunoreactivity was co-expressed by some substance P-IR (SP-IR) spinal ganglion neurons and extrinsic sensory fibers of aganglionic foals. Conclusions & Inferences: The presence of 5-HT4 in many enteric and extrinsic sensory neurons and nerve fibers provides solid morphological evidence of the cellular sites of 5-HT4 expression in horses. The evidence of SP-IR sensory neurons positive for 5-HT4 suggests its role in visceral sensitivity