A single injection of 100 micrograms reserpine into the crop of the medicinal leech, Hirudo medicinalis, reduced CNS serotonin and dopamine levels to less than 1% of control values within 3 d. High-pressure liquid chromotography- (HPLC) determined CNS serotonin and dopamine levels remained maximally depressed for approximately 1 month following reserpine injection. Subsequently, amine levels re...

Oviposition is induced upon mating in most insects. Ovulation is a primary step in oviposition, representing an important target to control insect pests and vectors, but limited information is available on the underlying mechanism. Here we report that the beta adrenergic-like octopamine receptor Octβ2R serves as a key signaling molecule for ovulation and recruits protein kinase A and Ca(2+)/cal...

Ritualized fighting between conspecifics is an inherently dangerous behavioral strategy, optimized to secure limited resources at minimal cost and risk. To be adaptive, potential rewards, and costs of aggression must be assessed to decide when it would be more opportune to fight or flee. We summarize insights into the proximate mechanisms underlying this decision-making process in field cricket...

Akinori Hirashima, Tomohiko Eiraku, Eiichi Kuwano, Eiji Taniguchi, and Morifusa Eto 1 Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, Fukuoka 812–8581, Japan 2 Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6–10–1 Hakozaki, Higashi–ku, Fukuoka 812–8581, Japan 3 School of Agriculture, Kyushu Tokai University, Kumamoto 8...

18 Stick insect middle leg (mesothoracic) motoneurons receive tonic excitatory input during front leg 19 stepping on a treadmill. We studied the pharmacology of this excitatory input to the motoneurons 20 during single-legged treadmill walking (in situ). During bath application of drugs restricted to the 21 mesothoracic ganglion activity in motoneurons contralateral to the stepping front leg wa...

Ianthellamide A (1), a novel octopamine derivative, was isolated from the Australian marine sponge Ianthella quadrangulata. Compound 1 selectively inhibited the activity of kynurenine 3-hydroxylase with an IC(50) value of 1.5 μM. It also significantly increased the level of endogenous kynurenic acid in rat brain and hence has the potential as a neuroprotective agent in the treatment of neurodeg...

Biogenic amines like dopamine or octopamine modify neural function at multiple levels, sensitizing or depressing behaviour. Recent studies in insects have now shown that, besides a role in motivational modulation, biogenic amines substitute the reinforcer function in associative learning, thus instructing the nervous system about the relevance of external events.