Neuroanatomical investigation of the gonadotrophin-releasing hormone 1 system in the seasonally breeding Cape dune mole-rat, Bathyergus suillus.

The gonadotrophin-releasing hormone 1 (GnRH1) system has been investigated immunohistochemically in Cape dune mole-rats (Bathyergus suillus), subterranean rodents that normally display severe aggression towards conspecifics. These animals breed seasonally and show a reduced mean plasma level of luteinising hormone during the non-breeding season. GnRH1-immunoreactive (ir) cell bodies and processes are found in the septal/preoptic area and the mediobasal hypothalamus; the cell bodies are found in equal measure in these two regions. Dense aggregations of GnRH1-ir fibres are present in the organum vasculosum of the lamina terminalis and the external zone of the median eminence. The total number of detectable GnRH1-ir cell bodies does not differ between the sexes or within the sexes between breeding and non-breeding seasons. Similarly there is no difference in the distribution of detectable GnRH1-ir cell bodies in male and female mole-rats in and out of the breeding season. Although the average size of GnRH1-ir cell bodies does not differ between the seasons in males, their size in females is significantly smaller in the non-breeding season. Whether this reduced size reflects reduced GnRH1 synthesis remains to be determined.

The pituitary potential for opportunistic breeding in the Cape dune mole-rat, Bathyergus suillus.

In this paper we investigated the effect of sex and season on baseline and post-GnRH challenge luteinising hormone (LH) levels in a solitary, seasonally breeding mole-rat. Circulating basal concentrations of luteinising hormone (LH) were found to differ significantly with season in both sexes. However, no significant difference was found in circulating basal LH concentration between the sexes either within or out of the breeding season. The magnitude of the LH response to an exogenous pharmacological overdose of GnRH both in and out of the breeding season in males and females respectively was not significant. This finding suggests that there is no down regulation of GnRH receptors on the pituitary during the non-breeding season. Cape dune mole-rats thus have the potential for opportunistic breeding outside of the typical breeding period. We argue that this represents an adaptation to limited and brief opportunities for mating in this xenophobic and aggressive species.

Identification of patient, medical and nursing staff attitudes to postoperative opioid analgesia: stage 1 of a longitudinal study of postoperative analgesia.

Sixty-one successive patients undergoing routine cholecystectomy together with all the registered nursing staff and junior doctors working on the surgical wards in a major teaching hospital were studied by means of questionnaires. These were designed to identify beliefs and attitudes to postoperative analgesia in the hospital. The survey revealed that there is a continuing prevalence among medical and nursing staff of attitudes and practices likely to contribute to poor postoperative analgesia. Patients had low expectations of pain relief and displayed reluctance to request analgesia. Injections were generally effective when given, but dosing intervals were often too long for good analgesia. With this knowledge it has been possible to devise strategies to counteract those attitudes leading to poor analgesia and these have formed the basis of a new Acute Pain Service. It is intended to repeat this survey at 3 yearly intervals in order to monitor progress.