Evidence for the involvement of a SchistoFLRF-amide-like peptide in the neural control of locust oviduct

Abstract

The presence of a SchistoFLRFamide-like peptide associated with the oviducts of Locusta migratoria has been shown using sequential reversed-phase high performance liquid chromatography separation coupled with radioimmunoassay and bioassay. The peptide is present in areas of the oviduct which receive extensive innervation, with sixfold less peptide in areas that receive little innervation. Material with FMRFamide-like immunoreactivity (determined by radioimmunoassay) is also present in the oviducal nerve and VIIth abdominal ganglion.SchistoFLRFamide is a potent modulator of contraction of this visceral muscle, inhibiting or reducing the amplitude and frequency of spontaneous contractions, relaxing basal tonus, and reducing the amplitude of neurally-evoked, proctolin-induced, glutamate-induced and high potassium-induced contractions. The FMRFamide-like immunoreactivity within the oviducts which co-elutes with SchistoFLRFamide on two separations is also capable of reducing the amplitude of neurally-evoked and proctolin-induced contractions, and of inhibiting spontaneous contractions and relaxing basal tonus.The effects of SchistoFLRFamide upon this visceral muscle are not abolished by the ~-adrenergic receptor antagonist phentolamine and do not appear to be mediated by cyclic AMP. Thus the receptors for Schisto-FLRFamide are distinct from those of octopamine which mediate similar physiological effects but which are blocked by phentolamine and which are coupled to adenylate cyclase.The results indicate that SchistoFLRFamide, or a very similar peptide, which has previously been identified as a modulator of locust heart beat, is also associat-Abbreviations: BPP-Bovine pancreatic polypeptide; BSA -Bovine serum albumin; EJP-Excitatory junctional potential; FaRPs -FMRFamide-related peptides; FLI-FMRFamide-like immunoreactivity; LMS -Leucomyosuppressin; RIA -Radioimmunoassay; RP-HPLC -Reversed-phase high performance liquid chromatography; TFA -Trifluoroacetic acid * To whom offprint requests should be sent ed with visceral muscle of the reproductive system, and may play a neural role in concert with octopamine, at modulating muscular activity.

The gifts that keep on giving: physiological functions and evolutionary dynamics of male seminal proteins in Drosophila

“…In either case, Acp26Aa action must ultimately affect reproductive tract tissues at or near the base of the ovary. To identify the molecular consequence of Acp26Aa action in the Drosophila female reproductive tract, we are presently examining these tissues for the role of Acps, and Acp26Aa in particular, in triggering vesicle exocytosis and/or alteration in levels of neuromodulators that cause muscle contraction and thus might be involved in inducing ovulation (Trent et al, 1983;Lange et al, 1986Lange et al, , 1991Bamji and Orchard, 1995;Lange and Nykamp, 1996;Monastirioti et al, 1996;Yamauchi et al, 1997;Waggoner et al, 1998). In summary, Acp26Aa (ovulin) has been identified as a mediator of one specific step in the egg-laying process: the release of mature oocytes from the ovary.…”

An unusual myosuppressin from the blood-feeding bugRhodnius prolixus

“…For example, they have been shown to inhibit spontaneous contractions of the heart in Calliphora vomitora (Duve et al, 1993) and Protophormia terraenovae (Angioy et al, 2007), the midgut and oviducts in Locusta migratoria (Lange and Orchard, 1998;Lange et al, 1991), and the hindgut in Leucophaea maderae (Holman et al, 1986). Myosuppressins also inhibit food intake in Blattella germanica (Aguilar et al, 2004), they possess anti-feeding properties in Spodoptera littoralis (Vilaplana et al, 2008) and feeding state alters the content of FLPs in endocrine-like cells in the midgut of L. migratoria (Lange, 2001).…”

A neurohormonal role for serotonin in the control of locust oviducts

“…These neurochemicals include proctolin , FMRFamide-related peptides (Lange et al, 1991), and also octopamine (Orchard and Lange, 1985), each of which appears to be associated with the direct innervation of locust oviducts. There are numerous other examples of neuropeptides and amines also influencing oviduct contraction but for which there is no evidence of direct innervation.…”