Background: Cone snails are a natural source of complex peptides with analgesic properties called conotoxins. These peptides are secreted in a complex venomic mixture and are predominantly smaller than 5 kDa. The present study aimed to document the analgesic activity of two species of CONUS coronatus (C. coronatus) and CONUS frigidus (C. frigidus) venom collected off the Iranian coast in a mouse behavioral test. Methods: Conotoxin containing fractions was extracted from the venom ducts and initially purified by column chromatography. The analgesic effect of the fractions was determined on formalin pain model and hot-plate test. Results: The results led to the identification of four fractions with analgesic activity in C. coronatus and two in C. frigidus. Only one fraction was able to reduce the flinching and licking in both acute pain and chronic pain phases of the formalin test. Moreover, the activity of this fraction remained 30 minutes on the hot-plate test. Purification of the fractions was carried out by RP-HPLC. LC-ESI-MS analysis of the fractions showed that the conotoxins of the analgesic fraction had molecular weights not previously reported. Conclusion: The findings give insight into the venom of two previously under-investigated CONUS species and reveal the therapeutic potential of the containing conopeptides.

Background and Aim: CONUS medullaris dermoid cysts are benign lesions, usually observed in the lumbosacral region of the spinal canal. Such lesions are often associated with congenital dermal sinus tracts and spinal dysraphism. Case Presentation: We reported a 37-year-old man with progressive paralysis distal part of the left lower limb presented to our clinic. The MRI of the lumbar spine, as a modality of choice, has revealed a well-defined sausage-shaped lesion, a multilobular cyst, and the heterogeneous contrast enhancement of an intra-and extra-medullary lesion in the CONUS medullaris region. Conclusion: Subtotal microsurgical resection was performed on the lesion. The result of histopathological examination confirmed the dermoid cyst, as well. After conducting the subtotal resection, an appropriate clinical result was achieved in the patient.

Dear EditorFinding a safe location for spinal block during surgical procedures is a matter that requires attention. CONUS medullaris (CM) is the most distal point of the spinal cord and dura that could be visualized on the sagittal sequence. CM location follows a normal distribution, from the lower third of L1 (ranging from the middle third of T12 to the upper third of L3) [1].