In a childs developing brain, lead interferes with synapse formation  in the cerebral cortex, neurochemical development (including that of neurotransmitters), and organization of ion channels. It causes loss of neurons myelin sheaths, reduces numbers of neurons, interferes with neurotransmission, and decreases neuronal growth.Lead-ions (Pb2+), like magnesium-ions (Mg2+), block NMDA receptors. Therefore, an increase in Pb2+ concentration will effectively inhibit ongoing long-term potentiation (LTP), and lead to an abnormal increase in long-term depression (LTD) on neurons in the affected parts of the nervous system. These abnormalities lead to the indirect downregulation of NMDA-receptors, effectively initiating a positive feedback-loop for LTD. The targeting of NMDA receptors is thought to be one of the main causes for leads toxicity to neurons. Diagnosis
Diagnosis includes determining the clinical signs and the medical history, with inquiry into possible routes of exposure. Clinical toxicologists, medical specialists in the area of poisoning, may be involved in diagnosis and treatment. The main tool in diagnosing and assessing the severity of lead poisoning is laboratory analysis of the blood lead level (BLL). Blood film examination may reveal basophilic stippling of red blood cells (dots in red blood cells visible through a microscope), as well as the changes normally associated with iron-deficiency anemia (microcytosis and hypochromasia). This may be known as sideroblastic anemia. However, basophilic stippling is also seen in unrelated conditions, such as megaloblastic anemia caused by vitamin B12 (colbalamin) and folate deficiencies.
Alosetron, sold under the brand name Lotronex among others, is a 5-HT3 antagonist used for the management of severe diarrhea-predominant irritable bowel syndrome (IBS) in women only. It was patented in 1987 and approved for medical use in 2002. It is currently marketed by Prometheus Laboratories Inc. (San Diego). Alosetron was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability and use restricted. Medical uses
Alosetron is indicated only for women with severe diarrhea-predominant irritable bowel syndrome (IBS-D) who have: 

chronic IBS symptoms (generally lasting 6 months or longer),
had anatomic or biochemical abnormalities of the gastrointestinal tract excluded, and
not responded adequately to conventional therapy.Severe IBS-D includes: diarrhea and 1 or more of the following:

frequent and severe abdominal pain/discomfort,
frequent bowel urgency or fecal incontinence,
disability or restriction of daily activities due to IBS. Efficacy
The phase III trial for approval was published in 2000 as an industry-funded randomised, placebo-controlled trial (PCT). Its authors found 1 mg alosetron, taken orally twice daily for 12 weeks, was associated with a 12% (CI 4.7-19.2) improvement in relief from abdominal pain and discomfort associated with diarrhoea-predominant patients. The prescription of alosetron is currently approved in the U.S. at 0.5 and 1 mg.The FDA Medical Officers Review, dated November 4, 1999, noted: "Patients considered by investigators to fit the diarrhea-predominant subtype had at baseline... stool consistency values that were neither loose nor watery".