Myoelectrical activity of the gastrointestinal tract of sheep analysed by computer.

The myoelectrical activity of several sections of the digestive tract of sheep has been studied as an estimation of the gastrointestinal motility. Nickel/chromium electrodes were implanted chronically in the reticulum, rumen, omasum, antrum and duodenum. The myoelectrical signals were then recorded simultaneously and stored in a computer which calculated the integrated activity, duration and period (interval) of each separate reticuloruminal spike burst and the integrated activity (over one minute intervals) in the omasum, abomasum and duodenum. The different electromyographic parameters were standardised in sheep during a period of non-ingestion (resting period), and the physiological changes in these parameters associated with rumination and feeding were measured. The main effect induced by rumination was an increase in the myoelectrical parameters in the reticulum. Feeding enhanced the total activity in all regions studied. In the reticulorumen this increase was due to a rise in the frequency of the spike bursts, although there was a decrease in the integrated activity and duration of each individual spike burst.

Involvement of neuronal nitric oxide synthase (nNOS) in the regulation of migrating motor complex (MMC) in sheep.

The objectives of this study were to evaluate the role of nitric oxide (NO) synthase isoforms (nNOS, eNOS, and iNOS) in the regulation of the migrating motor complex (MMC) in sheep using electromyography and their expression in the gastrointestinal (GI) tract by Western blot (WB) and immunohistochemistry. Intravenous administration of L-NAME or the nNOS inhibitor 7-nitroindazole (7-NI) decreased the MMC interval. Myoelectric activity of intestinal phase II was increased, whereas antral activity was reduced. These effects were blocked by L-arginine. Inhibitors of either iNOS (aminoguanidine and S-methylisothiourea) or eNOS (L-NIO) were ineffective. The NO donor sodium nitroprusside decreased GI myoelectric activity, inhibited the MMC pattern, and prevented the effects induced by L-NAME and 7-NI in the intestine. Intracerebroventricular administration of these agents did not modify GI motility. In the rumen, abomasal antrum, duodenum, and jejunum, WB showed three bands at about 155, 145, and 135kDa corresponding to nNOS, and a 140-kDa band (eNOS); however iNOS was not detected. Positive nNOS immunostaining was observed in neurons of the myenteric and submucous plexus of all GI tissues, while eNOS was found in the endothelial cells, ruminal and intestinal epithelium, as well as in some enteric neurons and in endocrine-like cells of the duodenal Brunner's glands. In contrast, only weak iNOS immunoreactivity was found in ruminal epithelium. Taken together, our results suggest that NO, synthesized at a peripheral level by nNOS, is tonically inhibiting the MMC pattern and intestinal motility in sheep.

The present Pyrenean population of bearded vulture (Gypaetus barbatus): its genetic characteristics.

The Pyrenean population of the endangered bearded vulture (Gypaetus barbatus) is the largest natural population in Europe. In this study, its current genetic variability was assessed using 110 animals of the recent population in order to know what the present situation. Sex identification by DNA methodology in the 110 bearded vultures, mitochondrial DNA (mtDNA) and eight microsatellite markers in 87 bearded vultures have been analysed. Our results for sex identification present a number of 49 males and 61 females; no significant differences for number of males and females in this population have been observed. mtDNA studies indicate that nucleotide and haplotype diversities and number of variable sites were low. Tajima's D test and Fu and Li's D* and F* tests suggest that mutations are selectively neutral and the population is expanding. A mean number of alleles per locus and a mean observed heterozygosity have been obtained by microsatellite analysis. FIS is not high, and inbreeding depression could be discarded in the near future. The results suggest that the Pyrenean population of bearded vultures have to be controlled in order to avoid the loss of genetic variability. This data should be taken into account when considering conservation plans for the species.

Bilateral Leydig cell tumor in a six-year-old intersex goat affected by Polled Intersex Syndrome.

A 6-year-old, sterile, Blanca Celtibérica breed adult doe was referred to our faculty. The doe had external female genitalia, a short anogenital distance, and normally shaped udders. Masculinization signs in the head shape and male behavior were also noted at the time of referral. Genetic analysis demonstrated normal 2n = 60 XX karyotype and an absence of the sex-determining region Y (SRY). The animal was homozygous for a DNA deletion responsible for the Polled Intersex Syndrome (PIS). A uterus and 2 uterine horns were present at the postmortem examination. Gartner's ducts and degenerated Wolffian derivatives persisted. There were 2 intra-abdominal testicle-like structures, one of which consisted of epididymal and deferent ducts. An advanced Leydig cell tumor, resulting in almost total destruction of the intratesticular structures, was also observed. Leydig cell tumors usually produce testosterone. Thus, these histologic findings are compatible with the evident virilization.