Serotonin induces or inhibits neuritic regeneration of leech CNS neurons depending on neuronal identity

Recovery of motor function after central nervous system (CNS) injury is dependent on the regeneration capacity of the nervous system, which is a multifactorial process influenced, among other things, by the role of neuromodulators such as serotonin. The neurotransmitter serotonin can promote neuronal regeneration but there are also reports of it causing restriction, so it is important to clarify these divergent findings in order to understand the direct scope and side effects of potential pharmacological treatments. We evaluated the effect of serotonin on the extent of neuritic outgrowth and morphology of three different neuronal types in the leech Haementeria officinalis during their regeneration in vitro: Retzius interneurons (Rz), annulus erector (AE) motoneurons, and anterolateral number 1 (AL1) CNS neurons. Neurons were isolated and cultured in L15 medium, with or without serotonin. Growth parameters were registered and quantified, and observed differences were analyzed. The addition of serotonin was found to induce AL1 neurons to increase their average growth dramatically by 8.3-fold (P=0.02; n=5), and to have no clear effect on AE motoneurons (P=0.44; n=5). For Rz interneurons, which normally do not regenerate their neurites, the addition of concanavaline-A causes substantial growth, which serotonin was found to inhibit on average by 98% (P=0.02; n=5). The number of primary neurites and their branches were also affected. These results reveal that depending on the neuronal type, serotonin can promote, inhibit, or have no effect on neuronal regeneration. This suggests that after CNS injury, non-specific pharmacological treatments affecting serotonin may have different effects on different neuronal populations.

Effect of lead pollution on anticoagulant effect of Whitmania pigra based on in vitro anticoagulation experiment / 中国中药杂志

Leech has a good anticoagulant activity and is one of the raw materials for treatment of many cardiovascular and cerebrovascular diseases. This study was based on in vitro anticoagulant experiments( APTT and PT) to investigate the effects of lead contamination on the anticoagulant effect of leech. At present,the Hirudo circulating in the market are dominated by Whitmania pigra,therefore Wh. pigra were cultivated under a different lead pollution for 50 days. Then,the effects of Wh. pigra extract,extracting from different cultivating environment,on activated partial thrombin time( APTT) and prothrombin time( PT) were determined by automatic coagulation instrument. The results showed that the Wh. pigra extract significantly prolonged the APTT compared with the saline group.The APTT of the lead-high residual Wh. pigra was shorter than that of the blank Wh. pigra. The Wh. pigra extracts from different treatment groups had little effect on PT. The results showed that the lead residue in the Wh. pigra increased with the increase of lead in the cultured soil,the lead residual of the Pb-H group was( 10. 66±2. 79) mg·kg~(-1),which exceeded the lead limit specified in the 2015 edition of the Chinese Pharmacopoeia. The results indicated that growth environment pollution is one of the important factors causing excessive lead in Wh. pigra. Lead pollution will reduce the anticoagulant effect of Wh. pigra and affect its clinical efficacy.

Helobdella nilae and Alboglossiphonia conjugata leeches as biological agents for snails control

The efficacy of leeches, as biological agents, in control of snail intermediate hosts of schistosomiasis [Bulinus truncatus, Biomphalaria alexandrina] and fascioliasis [Lymnaea natalensis] as well as their effect on the non-target snails Physa acuta, Melanioides tuberculata and Cleopatra bulimoides was evaluated. Two glossiphoniid snail leeches, Helobdella nilae and Alboglossiphonia conjugata were used. They destroyed egg masses and young snails more rapidly than adult ones. H. nilae showed a stronger destructive effect than A. conjugata. In a descending order, it preferred L. natalensis followed by B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and lastly C. bulimoides. But, A. conjugata preferred L. natalensis followed by B. truncatus, Ph. acuta, M. tuberculata, B. alexandrina and lastly C. bulimoides. The detailed diagnostic morphology and biology of the two leeches were given

Persistence of leech repellents on cloth.

Trials on persistence of repellent properties of N, N-diethyl phenyl acetamide (DEPA), N,N-diethyl-m-toluamide (DEET), 3acetyl2(2-6-dimethyl-5-heptenyl)oxazolidine(Citronyl) , dimethyl phthalate (DMP) and N-benzoyl piperidine (NBP) on cloth were conducted against land leeches in evergreen rain and deciduous forests of Assam. Results obtained were compared with volatile oil of Zanthoxylum armatum DC. syn. Z. alatum Roxb (Timur) to evaluate its efficacy as leech repellent. DEPA and DEET were found to be the best. Timur oil was at par with Citronyl and exhibited better results than DMP and NBP.