Motilin Receptor Expression Found in the Human Main and Accessory Lacrimal Glands.

INTRODUCTION: In this study, we investigated the presence of motilin receptors (MR) in adnexal tissue including the human main lacrimal gland. METHOD: 17 adnexal human specimens comprising of 11 isolated human main lacrimal gland specimens, four full-thickness human eyelid excisions and two exenterations containing full-thickness eyelid and portions of the main lacrimal gland were immunolabelled with a rabbit polyclonal human MR antibody. RESULTS: Our results demonstrated that all main lacrimal gland specimens (13/13, 100%) were positive for MR expression with a predominance (10/13 (77%) of grade 1+ punctate distribution. Motilin receptors were not found in eccrine glands, cutaneous sebaceous glands, glands of Zeis or glands of Moll (0/6, 0%). We also confirmed MR expression in the accessory lacrimal gland tissue. CONCLUSION: In summary, we discovered the MR receptor in the lacrimal and accessory lacrimal gland - the significance of which, in the lacrimal gland, remains unclear - but motilin may play a role in the muscarinic control of aqueous tear secretion.

The First Case Report of Schnitzler Syndrome Presenting with Eye Pain.

Schnitzler syndrome is a rare, auto inflammatory condition known to manifest with bone pain, urticarial rash, fevers, relapsing arthralgia, and fatigue. In this case report, we describe a patient who was diagnosed with Schnitzler Syndrome that had initially presented with a unilateral pressure-type headache with a sensation of a 'dagger' stabbing into the back of the eye. He also had an associated ipsilateral redness of the conjunctiva, eyelid swelling, subtle optic disc elevations bilaterally and facial flushing - but with no visual acuity, pupillary, or lacrimatory changes. Anterior segment, fundoscopy, intraocular pressures and extraocular muscle movements were otherwise normal.

Kynurenine Aminotransferases and the Prospects of Inhibitors for the Treatment of Schizophrenia.

Schizophrenia is a complex neuropsychiatric disorder with limited treatment options and highly debilitating symptoms, leading to poor personal, social, and occupational outcomes for an afflicted individual. Our current understanding of schizophrenia suggests that dopaminergic and glutamatergic systems have a significant role in the pathogenesis of the disease. Kynurenic acid, an endogenous glutamate antagonist, is found in elevated concentrations in the prefrontal cortex and cerebrospinal fluid of patients with schizophrenia, and this affects neurotransmitter release in a similar manner to previously observed psychotomimetic agents, such as phencyclidine, underlining the molecular basis to its link in schizophrenia pathophysiology. Kynurenic acid is a breakdown product of tryptophan degradation, through a transamination process mediated by kynurenine aminotransferase (KAT) enzymes. There are four KAT homologues reported, all of which are pyridoxal 5'- phosphate-dependent enzymes. All four KAT isoforms have been analysed structurally and biochemically, however the most extensive research is on KAT-I and KAT-II. These two enzymes have been targeted in structure-based drug design as a means of normalising raised kynurenic acid levels. The most potent KAT-I inhibitors and KAT-II inhibitors include phenylhydrazone hexanoic acid derivatives and a pyrazole series of compounds, respectively. KAT inhibitors have been shown to be effective in reducing kynurenic acid production, with accompanying changes in neurotransmitter release and pro-cognitive effects seen in animal studies. This review will discuss the characteristics pertaining to the different KAT isoforms, and will highlight the development of significant KAT inhibitors. KAT inhibitors have great potential for therapeutic application and represent a novel way in treating schizophrenia.