SHORT COMMUNICATION ALLATOTROPIN IS A CARDIOACCELERATORY PEPTIDE IN

Division of Neurobiologyof the Arizona Research Laboratories of the University of Arizona, Tucson,AZ 85721, USAAccepted 20 October 1993Allatotropin is a neuropeptide that was originally isolated from the sphinx mothManduca sexta,in which it stimulates the synthesis of juvenile hormone in adults(Kataoka et al. 1989). An antiserum raised against this peptide was characterized, shownto be specific for allatotropin and used in a competitive enzyme-linked immunosorbentassay (ELISA) to demonstrate that allatotropin is present not only in the brain andretrocerebral complex but also in the ventral nerve cord of Manduca sexta (Veenstra andHagedorn, 1993). In the present study, allatotropin-immunoreactive neurons were locatedusing the allatotropin antiserum in a whole-mount immunofluorescence method adaptedfrom Davis et al. (1989). Several cell types were found to be immunoreactive, includingthree pairs of intensely staining median neurons in abdominal ganglia 3–6 of the pharateadult. The location of these median pairs of cells in each ganglion is anterior, mid-dorsaland posterio-ventral (Fig. 1A). The cells project bilaterally via the ventral nerves of eachganglion to the next transverse nerve (Fig. 2), where their axons terminate in numeroussuperficial varicosities (Fig. 1D). It is well established that the transverse nerve is aneurohemal organ in Lepidoptera (Provansal, 1972; Taghert and Truman, 1982; Tublitzand Truman, 1985 a–d). The location and projection pattern of these three pairs of medianneurons indicate that they belong to a group of abdominal median neurosecretory cellsidentified previously (Taghert and Truman, 1982; Tublitz and Truman, 1985 a). Using thenomenclature of Davis et al.(1993), these are the M