Cyclic GMP levels and guanylate cyclase activity in pheromone-sensitive antennae of the silkmoths Antheraea polyphemus and Bombyx mori

Abstract

Female sex pheromones applied to freshly isolated, living antennae of male Antheraea polyphemus and Bombyx mori led to an increase of cGMP. A 1:1 mixture of 2 pheromone components of Antheraea polyphemus blown for 10 sec in physiological concentrations over their antennal branches raised cGMP levels about 1.34-fold (+/- 0.08 SEM, n = 23) from a basal level of 3.0 +/- 0.6 (SEM, n = 20) pmol/mg protein. Similarly, bombykol elicited a 1.29-fold (+/- 0.13 SEM, n = 23) cGMP increase in antennae of male Bombyx mori from a basal level of 2.7 +/- 0.5 (SEM, n = 24) pmol/mg protein. No cross-sensitivity was found with respect to pheromones from either species. In antennae of female silkmoths, the cGMP response was missing upon stimulation with their own respective pheromones according to the known lack of pheromone receptor cells in the female. cAMP levels in the male antennae of 14.2 +/- 2.9 (SEM, n = 4) pmol/mg protein in A. polyphemus and 15.0 +/- 3.0 (SEM, n = 5) pmol/mg protein in B. mori were not affected by pheromone stimulation. Within 1–60 sec, the extent of cGMP increase in B. mori was independent of the duration of pheromone exposure. The levels of cGMP in pheromone- stimulated antennae of both species remained elevated for at least 10 min, i.e., much longer than the duration of the receptor potential measured in single-cell recordings. Guanylate cyclase activity was identified in homogenates of male and female antennae from both species. The Km of the guanylate cyclase from male B. mori for the preferential substrate MnGTP was 175 microM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation in pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta

“…Because two of these channel types (which share properties with trp-and trpl-like channels) are permeable to Ca 2+ and because both are closed in a Ca 2+ -dependent manner, it is very likely that intracellular Ca 2+ rises caused by these channels are involved in short-term adaptation, as has been shown in Drosophila (Störtkuhl et al, 1999;Montell, 2001). Biochemical and physiological evidence suggests the involvement of cGMP (Ziegelberger et al, 1990;Boekhoff et al, 1993;Stengl et al, 2001;Dolzer, 2002) together with Ca 2+ concentration rises (Stengl, 1993(Stengl, , 1994Dolzer et al, 1999) in long-term adaptation in moths. Thus, it is likely that Ca 2+ -and cGMP-dependent mechanisms affect the rising phase of the sensillar potential in response to long and very strong pheromone stimuli.…”

“…long-lasting) adaptation (Ziegelberger et al, 1990;MarionPoll and Tobin, 1992;Boekhoff et al, 1993;Stengl et al, 2001;Dolzer, 2002).…”

Intracellular regulation of the insect chemoreceptor complex impacts odor localization in flying insects

“…PKC activity analyses were performed according to Ziegelberger et al (1990) and Maida et al (2000). Briefly, olfactory antennae of Drosophila were cut under a binocular light microscope using fine forceps and the isolated antennae were immediately stimulated with a headspace mixture of odours (ethyl hexanoate, ethyl butyrate, ethyl acetate, methyl acetate, 2,3-butanedione, 2-heptanone, 1-hexanol, pentyl acetate, ethyl-3-hydroxybutyrate).…”

Deterrence of feeding in Rhodnius prolixus (Hemiptera: Reduviidae) after treatment of antennae with a nitric oxide donor

“…An elevated concentration of cGMP reduces the pheromone induced IP3 response, suggesting that cGMP could be involved in the adaptation of the antennal receptors cells of Heliothis virescens (Boekhoff et al, 1993). The regulation of the generation of cGMP through the activation of guanilate cyclase, responsible for cGMP synthesis, is involved in the adaptation of the olfactory cells of Antheraea polyphemus and Bombix mori (Ziegelberger et al, 1990). These results are also supported by the finding of different types of guanilate cyclase in M. sexta (Simpson et al, 1999;Nighorn et al, 2001;Stengl et al, 2001;Morton & Nighorn, 2003).…”