Identification of functional intramuscular rectal mechanoreceptors in aganglionic rectal smooth muscle from piebald lethal mice.

The mechanosensitive endings of low-threshold, slowly adapting pelvic afferents that innervate the rectum have been previously identified as rectal intraganglionic laminar endings (rIGLEs) that lie within myenteric ganglia. We tested whether the aganglionic rectum of piebald-lethal (s(l)/s(l)) mice lacks rIGLEs and whether this could explain impaired distension-evoked reflexes from this region. Extracellular recordings were made from fine rectal nerves in C57BL/6 wild-type and s(l)/s(l) mice, combined with anterograde labeling. In C57BL/6 mice, graded circumferential stretch applied to the rectum activated graded increases in firing of slowly adapting rectal mechanoreceptors. In s(l)/s(l) mice, graded stretch of the aganglionic rectum activated similar graded increases in rectal afferent firing. Stretch-sensitive afferents responded at low mechanical thresholds and fired more intensely at noxious levels of stretch. They could also be activated by probing their receptive fields with von Frey hairs and by muscle contraction. Anterograde labeling from recorded rectal nerves identified the mechanoreceptors of muscular afferents in the aganglionic rectal smooth muscle. A population of afferents were also recorded in both C57BL/6 and s(l)/s(l) mice that were activated by von Frey hair probing, but not stretch. In summary, the aganglionic rectum is innervated by a population of stretch-sensitive rectal afferent mechanoreceptor which develops and functions in the absence of any enteric ganglia. These results suggest that in patients with Hirschsprung's disease the inability to activate extrinsic distension reflexes from the aganglionic rectum is unlikely to be due to the absence of stretch-sensitive extrinsic mechanoreceptors.

From biopolitics to bioethics: church, state, medicine and assisted reproductive technology in Ireland.

This paper examines the emerging bioethical debate on assisted reproductive technology (ART) in Ireland, which is shaped by the long-standing contentious issue of abortion and the constitutional protection afforded to the 'unborn'. The focus of the paper is on the way in which the terms of this debate are shaped and constrained by the historical relations of power between church, state and medicine. Since the representation of Ireland as a post-Catholic, plural republic is becoming increasingly mainstream to cultural and political discourse, we pay particular attention to how the Catholic Church embraces bioethics as a meta frame or code for refocusing questions of values, beliefs and meanings to sustain the ideal of Ireland as a 'pro-life' and essentially Catholic nation. The Catholic Church is not simply asserting its voice of dissent in the context of public debate as one voice amongst a plurality of other voices, but to shape the emerging debate as a powerful, institutional actor. The opportunity to do so is afforded by the lack of public debate on bioethical issues and the exceedingly slow pace at which bioethics is moving towards an institutionalised framework in Ireland. These events can be explained by the legacy of the social power of the Catholic Church in Ireland and the direct and indirect influence it has long exercised over public policy vis-à-vis the state and its institutions, including medicine. There are two interconnected threads to the contextual analysis presented in our case study: first, the legacy of the social power wielded by the Catholic Church, and its slow and incremental demise reflected in the pace of secularisation in Ireland and the privatisation of morality; second, the emergence of a bioethical regulatory debate on ART, which is mired in the abortion controversy. Our analysis focuses on a number of key contradictions and tensions in the way in which the key institutions of church, state and medicine navigate their own positions vis-à-vis a bioethics debate, and how this constrains public participation.