The development of oesophageal hyperalgesia is prevented by physiologically increasing parasympathetic tone. This effect is pharmacologically blocked with atropine, providing evidence that the PNS influences the development of oesophageal pain hypersensitivity.

All applications of s.5(2) of the Mental Health Act 1983 (MHA) between January 1997 and December 1998 were examined to assess variables likely to affect outcome and to compare these findings to other similar published studies. Of the 154 applications (7% of all admissions), 56 were converted to s.3 and 39 to s.2 of the MHA. We found that the time of application, grade of doctor making the application and the day of application were the best predictors of outcome of s.5(2). Apart from a few exceptions, our findings were generally in keeping with previous published results. These findings suggest a national trend in the clinical use of s.5(2) and may provide a useful guide for those considering reform of this part of the MHA.

Clinically, pain can be sub-classified into superficial, neuropathic and deep pain. Deep pain as a result of stimulation to structures such as the viscera is the most poorly understood and notoriously difficult to treat. The dorsal horn of the spinal cord is the gateway to conscious nociception and it is at this point in the pain processing pathway that the peripheral afferent input can be enhanced or inhibited by several mechanisms, the most important being central sensitisation. Long-term potentiation, another mechanism, can also be elicited in the spinal cord. Here nociceptor activity and/or peripheral tissue inflammation produces long-term changes in synaptic efficacy in the dorsal horns. This plays a major role in the generation of acute post-operative and post-traumatic pain, migraine and neuropathic pain. Behavioural consequences of central sensitisation can even be readily detected in human psychophysical experiments. Another importantmechanism is ‘wind-up’, a form of homosynaptic activity-dependent plasticity characterised by a progressive increase in action potential output from dorsal horn neurones. There is an extensive body of literature which has highlighted the importance of central sensitisation. This review examines some of the most significant recent findings with regards to future pharmacology. As we are beginning to understand some of the mechanisms of central sensitisation and its importance in visceral pain, novel receptor sites have been identified, offering exciting possibilities with regards to future pharmacological development not only to visceral pain, but for pain management as a whole.

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Irritable bowel syndrome is in many ways still a famous ‘heartsinker’ but over the past half century a significantly better understanding of the pathophysiology has evolved, improving overall treatment.