Changes in the Distribution of Cocaine- and Amphetamine-Regulated Transcript-Containing Neural Structures in the Human Colon Affected by the Neoplastic Process.

The present study analysed changes in the distribution pattern of cocaine- and amphetamine-regulated transcript (CART) in the enteric nervous system (ENS) of the human colon challenged by adenocarcinoma invasion, using the double-labelling immunofluorescence technique. In control specimens, CART immunoreactivity was found in neurons of all studied plexuses, representing 30.1 ± 4.1%, 12.9 ± 5.2%, and 4.1 ± 1.3% of all neurons forming the myenteric plexus (MP), outer submucous plexus (OSP), and inner submucous plexus (ISP), respectively. Tumour growth into the colon wall caused an increase in the relative frequency of CART-like immunoreactive (CART-LI) neurons in enteric plexuses located in the vicinity of the infiltrating neoplasm (to 36.1 ± 6.7%, 32.7 ± 7.3% and 12.1 ± 3.8% of all neurons in MP, OSP and ISP, respectively). The density of CART-LI nerves within particular layers of the intestinal wall did not differ between control and adenocarcinoma-affected areas of the human colon. This is the first detailed description of the CART distribution pattern within the ENS during the adenocarcinoma invasion of the human colon wall. The obtained results suggest that CART probably acts as a neuroprotective factor and may be involved in neuronal plasticity evoked by the progression of a neoplastic process.

Myenteric plexuses atrophy in the vicinity of colorectal cancer tissue is not caused by apoptosis or necrosis.

INTRODUCTION: The previously performed studies showed that the presence of colorectal cancer (CRC) tumor is associated with the atrophy of myenteric plexuses in the vicinity of cancer invasion; however, the possible mechanisms of this phenomenon are not known. The aim of the present study was to determine whether the atrophic changes of the enteric nervous system (ENS) within an intestine wall of the CRC patients were caused by apoptosis or necrosis and whether they were associated with changes in the number of galanin-immunore-active (GAL-Ir) neurons. MATERIAL AND METHODS: Samples of the large intestine wall located close to the CRC invasion and control, distally-located part of the colon, were collected from 9 CRC patients. The size of ENS plexuses and the number of neurons were compared. Triple immunofluorescent staining was used to visualize the co-expression of caspase 3 (CASP3) or caspase 8 (CASP8) with GAL and protein gene-product 9.5 (PGP 9.5, panneuronal marker) in the submucosal and myenteric ENS plexuses. The cells expressing myeloperoxidase (MPO, marker of neutrophils) and CD68 (marker of macrophages) were detected by immunohistochemistry around/in myenteric plexuses (MPs) and in the muscularis externa of the colon wall in the vicinity of tumor invasion. RESULTS: Myenteric plexuses in the vicinity of the CRC tissue were significantly smaller and had lower number of neurons per plexus than distantly located plexuses. The number of CASP8- and CASP3-Ir neurons in the ENS plexuses was similar in the colon wall both close to and distally from tumor invasion. The number of CASP8-Ir neurons within MPs located close to CRC invasion was higher than of CASP3-Ir neurons. The percentage of neurons co-expressing CASP8 and GAL in myenteric plexuses close and distantly from tumor was three-fold lower than of those co-expressing CASP3 and GAL. The mean number of neutrophils and macrophages inside and around myenteric plexuses located close to tumor invasion was higher or similar, respectively, as compared with adjacent muscularis externa. CONCLUSIONS: The atrophy of myenteric plexuses in the vicinity of CRC invasion is not caused by apoptosis or necrosis. The differences in the proportions of neurons expressing galanin and the studied caspases suggest as yet unknown role of this neuropeptide in the mechanisms of neuron's atrophy in MPs located close to CRC tumor.

Relative transcript abundance of oxytocin receptor gene in porcine uterus during luteolysis and early pregnancy.

The aim of the present study was to investigate transcript localization of the oxytocin receptor (OTR) gene in different cells of the porcine uterus during luteolysis and early pregnancy (days 14-16) using in situ hybridization (ISH). OTR mRNA was localized in the uterine luminal epithelium (LEC), glandular epithelium (GEC), stromal cells (SC) of the endometrium, in the longitudinal muscle layer (LM) and circular muscle layer (CM) of the myometrium. The OTR transcript was quantified by optical density units of silver grains. The OTR transcript levels in the endometrium and myometrium were statistically higher during luteolysis than during early pregnancy (P<0.05). Besides, during luteolysis, the mRNA level was higher in the LEC, GEC of the endometrium and LM of the myometrium compared to that observed in the SC of endometrium and CM of the myometrium, respectively (P<0.05). In summary: 1) the level of OTR mRNA in uterine tissues is higher during luteolysis compared to early pregnancy, 2) the OTR transcript level in endometrial cells did not correspond to the sensitivity of these cells to oxytocin (OT), 3) the myometrial expression of the OTR gene is appropriate to control contractile activity and secretion of PG during luteolysis.

Mechanisms ensuring optimal conditions of implantation and embryo development in the pig.

The paper summarizes results of a series of studies concerning luteolysis and early pregnancy in pigs. The involvement of the oxytocin (OT)/OT receptor system in the mechanism of corpus luteum (CL) protection during early pregnancy as well as the implication of luteinizing hormone (LH) in the endometrial prostaglandin (PG) release and synthesis are described. In addition, the role of leptin in the regulation of ovarian steroidogenesis and the expression of leptin and its receptor (OB-Rb) genes in hypothalamus, pituitary and reproductive tissues are reported. Moreover, a strong emphasis was placed on the mechanism of PGE2 participation in the local endocrine regulations of reproductive processes occurring in the utero-ovarian area as well as on the vascular endothelial growth factor (VEGF) ligand-receptor system in the ovary and uterus.

In vitro contractile activity of porcine myometrium during luteolysis and early pregnancy: effect of oxytocin and progesterone.

The present study was undertaken to elucidate the role of OT in myometrial contractility in sows. Spontaneous and OT-stimulated contractions of the inner circular (CM) and outer longitudinal (LM) layers isolated from cyclic (Days 14-16) and early pregnant (Days 14-16) sows were examined in six cyclic and six pregnant sows. In addition, the role of P(4) in the modulation of OT-induced uterine contractions was investigated. The contractile activity of the LM and CM layers was recorded in a tissue chamber filled with Krebs-Ringer solution. Myometrial contractility was expressed as area under the contractility curve (AUC) and frequency of contractions. Myometrial longitudinal and circular muscles exhibited spontaneous contractility in sows during both luteolysis and early-pregnancy. The mean AUC was higher (p<0.05) in the LM layer compared to the CM layer in both cyclic and pregnant animals. In addition, pregnant sows were characterized by higher AUC in both LM and CM layers in comparison to cyclic sows. The CM layer was unresponsive to examined treatments. Oxytocin (1-3x10(-8) and 1-3x10(-7)M) increased the AUC and frequency of contractions of the LM layer in both examined animal groups, being more effective during luteolysis (p<0.001) than early pregnancy (p<0.01). Response of the LM layer to OT appeared to be clearly related to the initial spontaneous level of contractility. This response to OT was inhibited (p<0.05) in the presence of OT antagonist (10(-6)M). Moreover, in pregnant sows, OT-stimulated contractile activity of myometrium was inhibited (p<0.05) by P(4) (10(-5)M). In conclusion, OT receptors present in myometrial cells (especially in the LM layer) are involved in the regulation of contractile activity of porcine myometrium during luteolysis and early-pregnancy. In addition, progesterone appears to be involved in this regulation.

Oxytocin stimulates prostaglandin F2alpha secretion and prostaglandin F synthase protein expression in porcine myometrial tissue.

The possibility of PGF(2)alpha production and presence of prostaglandin F synthase (PGFS; PGD(2) 11-ketoreductase) was studied in control and oxytocin (OT)-stimulated myometrial slices isolated from cyclic (Days 14-16) and early pregnant (Days 14-16) sows. Oxytocin (10(-7) M) stimulated (p<0.01) PGF(2)alpha production in both cycling and early pregnant myometrial slices. Prostaglandin F(2)alpha release was higher (p<0.01) in control as well as OT-treated myometrium of early pregnant sows in comparison to cycling myometrium. Prostaglandin F synthase expression at protein level was evident in myometrial slices of cyclic as well as early pregnant sows. The signals of PGFS was stronger (p<0.05) in cycling myometrium exposed to OT compared to that of control. There were no significant differences (p>0.05) in PGFS protein expression between control and OT-stimulated myometrial tissue of early-pregnant sows. The results of this study indicate the local PGF(2)alpha synthesis and the presence of PGFS in porcine cycling and early pregnant myometrial tissue. In addition, OT increased PGD(2) 11-ketoreductase protein expression in myometrium harvested during the porcine estrous cycle. However, the OT-stimulated PGF(2)alpha myometrial secretion was observed in both, cycling and pregnant gilts.