Pheromonotropic and pheromonostatic activity in moths

Pheromone biosynthesis in many species of moths requires a pheromonotropic neurosecretion, the pheromone biosynthesis activating neuropeptide (PBAN), from the brain-subesophageal ganglion-corpora cardiaca complex. Some investigators suggest that PBAN is released into the hemolymph and acts directly on sex pheromone glands (SPG) via a Ca⁺⁺/calmodulin-dependent adenylate cyclase. Others suggest, however, that PBAN acts via octopamine that is released by nerves from the terminal abdominal ganglion innervating the SPG. These findings suggest that there are controversies on the mode of action of PBAN and other pheromonotropic factors, sometimes even within the same species. Mating in many insects results in temporary or permanent suppression of pheromone production and/or receptivity. Such a suppression may result from physical blockage of the gonopore or deposition of pheromonostatic factor(s) by the male during copulation that result in suppressed pheromone production and/or receptivity in females either directly or by a primer effect. In several species of insects, including moths, a pheromonostatic factor is transferred in the seminal fluid of males. Similar to the controversies associated with the pheromonotropic activity of PBAN, sometimes even within the same species, there appear to be controversies in pheromonostasis in heliothines as well. This paper reviews these conflicting findings and presents some data on pheromonostatic and pheromonotropic activity in Heliothis virescens that support and conflict with current information, raising further questions. Answers to some of the questions are partly available; however, they remain to be answered unequivocally. © 1994 Wiley-Liss, Inc.     

PBAN/pyrokinin peptides in the central nervous system of the fire ant, <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

The pyrokinin/pheromone-biosynthesis-activating neuropeptide (PBAN) family of peptides found in insects is characterized by a 5-amino-acid C-terminal sequence, FXPRLamide. The pentapeptide is the active core required for diverse physiological functions, including the stimulation of pheromone biosynthesis in female moths, muscle contraction, induction of embryonic diapause, melanization, acceleration of puparium formation, and termination of pupal diapause. We have used immunocytochemical techniques to demonstrate the presence of pyrokinin/PBAN-like peptides in the central nervous system of the fire ant, Solenopsis invicta. Polyclonal antisera against the C-terminal end of PBAN have revealed the location of the peptide-producing cell bodies and axons in the central nervous system. Immunoreactive material is detectable in at least three groups of neurons in the subesophageal ganglion and corpora cardiaca of all adult sexual forms. The ventral nerve cord of adults consists of two segmented thoracic ganglia and four segmented abdominal ganglia. Two immunoreactive pairs of neurons are present in the thoracic ganglia, and three neuron pairs in each of the first three abdominal ganglia. The terminal abdominal ganglion has no immunoreactive neurons. PBAN immunoreactive material found in abdominal neurons appears to be projected to perisympathetic organs connected to the abdominal ganglia. These results indicate that the fire ant nervous system contains pyrokinin/PBAN-like peptides, and that these peptides are released into the hemolymph. In support of our immunocytochemical results, significant pheromonotropic activity is found in fire ant brain-subesophageal ganglion extracts from all adult fire ant forms (queens, female and male alates, and workers) when extracts are injected into decapitated females of Helicoverpa zea. This is the first demonstration of the presence of pyrokinin/PBAN-like peptides and pheromonotropic activity in an ant species. This research was supported in part by a US-Israel Binational Science Foundation Grant (no. 2003367).     

Tissue localization and partial characterization of pheromone biosynthesis activating neuropeptide inAchaea janata

Female sex pheromone production in certain moth species have been shown to be regulated by a cephalic endocrine peptidic factor: pheromone biosynthesis activating neuropeptide (PBAN), having 33 amino acid residues. Antisera against syntheticHeliothis zea-PBAN were developed. Using these polyclonals, immunoreactivity was mapped in the nervous system ofAchaea janata. Three distinct groups of immunopositive secretory neurons were identified in the suboesophageal ganglion; and immunoreactivity was observed in the corpora cardiaca, thoracic and in the abdominal ganglia. From about 6000 brain sub-oesophageal ganglion complexes, the neuropeptide was isolated; and purified sequentially by Sep-pak and reversed phase high performance liquid chromatographic methods. Identity of purified PBAN fraction was confirmed with polyclonal antibody by immunoblotting. Molecular mass of the isolated peptide was determined by matrix-assisted laser desorption/ionization mass spectrometry, and was found to be 3900 Da, same as that of knownH. zea-PBAN. Radiochemical bioassay confirmed the pheromonotropic effect of the isolated neuropeptide in this insect     

A pheromonotropic peptide of Helicoverpa zea,with melanizing activity,interaction with PBAN,and distribution of immunoreactivity

The sequence of an 18-amino acid residue peptide was deduced from the gene encoding PBAN and other peptides with common C-termini in Helicoverpa zea. The peptide caused melanization in larvae and pheromone production in females of H. zea, and was designated pheromonotropic melanizing peptide (Hez-PMP). The peptide has a 83% sequence homology with a pheromonotropic peptide isolated from Pseudaletia separata. PMP caused melanization and mortality when injected into larvae just before molting. Whereas intense melanization was caused with a dose of 1,000 pmol, peak mortality occurred at 100 pmol, with 50% of larvae dying within 48 h after injection. Pheromonotropic activity of PMP was dose dependent. Co-injection of Hez-PMP and Hez-PBAN into a female resulted in suppression of the pheromonotropic effect of PBAN. Whole-mount immunocytochemical studies revealed PMP-like immunoreactivity in frontal ganglion, subesophageal, thoracic, and abdominal ganglia as well as the esophageal nerve.     

Control of pheromone biosynthesis in mated redbanded leafroller moths

Mating in the redbanded leafroller moth, Argyrotaenia velutinana, causes a permanent decline in pheromone titers. Three hours following the termination of mating, phermone titers were significantly decreased from premating levels, and titers remained low for at least four days after mating. Pheromone titers were similar in females that had been decapitated or mated for twenty-four hours. In the redbanded leafroller moth, two peptides control pheromone production. The pheromone biosynthesis activating neuropeptide is produced in the brain and the pheromonotropic bursa peptide is produced in the corpus bursae. Both peptides stimulated pheromone biosynthesis in mated females and extracts prepared from brains and bursae of mated females contained pheromonotropic activity. However, severing the ventral nerve cord before mating prevented the decline in pheromone titer that occurred in mated females. Hemolymph collected during scotophase from mated females did not have pheromonotropic activity, whereas hemolymph collected during scotophase from virgin females contained activity. These results indicate that mating produces a signal sent by the ventral nerve cord to the brain to stop the release of pheromone biosynthesis activating neuropeptide. © 1993 Wiley-Liss, Inc.     

Termination of sex pheromone production in mated females of the silkworm moth

A mating duration of more than 6 h was necessary to permanently terminate the production of the sex pheromone (bombykol) in the silkworm moth, Bombyx mori L. (Lepidoptera: Bombycidae), although the female formed a bursa copulatrix including a spermatophore and laid fertilized eggs even after mating for only 0.5 h. The 6-h mated female again produced bombykol if given an injection of synthetic pheromonotropic neuropeptide (PBAN), which is known to activate pheromone biosynthesis in a virgin female. Extracts of brain-suboesophageal ganglion (SG) complexes, which were removed from 6- and 24-h mated females, showed strong pheromonotropic activities. These results indicated that the pheromone gland of the mated female maintained its ability to biosynthesize bombykol; however, it could not produce pheromone due to a suppression of PBAN secretion from the SG. Furthermore, bombykol titers did not decrease after mating in females with a transected ventral nerve cord, even after the injection of a spermatophore extract, suggesting that the suppression of PBAN secretion was mediated by a neural signal and not by a substance in the spermatophore. The mated females accumulated (10E, 12Z)-10,12-hexadecadienoic acid, a precursor of bombykol biosynthesis, in their pheromone glands as did decapitated females. © 1996 Wiley-Liss, Inc.     

Stimulation of sex pheromone production by proteinaceous extracts of the bursa copulatrix in the redbanded leafroller moth

Pheromone biosynthesis in the redbanded leafroller moth, Argyrotaenia velutinana, was stimulated by homogenates of the bursa copulatrix. Although pheromonotropic activity was also extractable from the ovary, the activity of pheromone biosynthesis activating neuropeptide (PBAN) or bursa extracts was not impaired in isolated abdomens by removal of the ovary. Response to the bursa extracts was dependent on the dose administered and the time of incubation. Amounts of pheromone present in adult females of different ages appeared to be correlated with the extractable amount of pheromonotropic activity from their bursa copulatrix. Decapitation did not result in the suppression of burse factor production. Homogenates of the bursa elicited similar effects in both isolated gland and isolated abdomen incubations, but the brain neuropeptide, PBAN, was less active in the former than in the latter. Bursa extracts stimulated pheromone production in isolated abdomen incubations deprived of the bursa copulatrix, but PBAN did not. Loss of activity of bursa homogenates after treatment with either pronase E or carboxypeptidase Y indicated that the pheromonotropic factor is a proteinaceous substance. The mechanism through which pheromone production is regulated in redbanded leafroller moths is discussed. © 1992 Wiley-Liss, Inc.     

The distribution of PBAN (pheromone biosynthesis activating neuropeptide)-like immunoreactivity in the nervous system of the gypsy moth,Lymantria dispar

The production of sex pheromone in many moths is regulated by the neuropeptide PBAN (pheromone biosynthesis-activating neuropeptide). Studies in a number of species have shown that pheromone production can be linked to a hemolymph factor and that continuity in the ventral chain of ganglia is not required. However, it has recently been shown that production of pheromone in the gypsy moth, Lymantria dispar, is largely prevented in females with a transected ventral nerve cord (VNC). To begin to understand the cellular basis for this dependence on the VNC, we sought to determine the distribution of PBAN in the central nervous system and its neurohemal sites, including those associated with the VNC. Using an antiserum to L. dispar-PBAN in immunocytochemical methods, we have mapped the distribution of PBAN-like immunoreactivity (PLI). PLI is found in three clusters of ventral midline somata in the subesophageal ganglion (SEG), in three clusters of midline cells in each segmental ganglion, and in bilateral pairs of cells located posterolaterally in each abdominal ganglion. The SEG cells comprise both interneurons, with endings in the neuropil of each segmental ganglion, as well as neurosecretory cells, with endings in the retrocerebral complex and in an unusual neurohemal structure near the anterior aspect of the SEG. The latter structure, which we have named the corpus ventralis, receives axons from the two anterior clusters of cells in the SEG. In the abdominal ganglia, the posterolateral clusters of cells have immunoretroreactive axons exiting the ganglia via the ventral nerves. Endings of these axons reach the perivisceral organ in the next posterior ganglion and pass anteriorly into the median nerve, forming additional varicose endings. We did not detect PLI in the terminal nerve. Thus, our findings raise the possibility that the requirement for an intact VNC in pheromone production reflects a role for descending regulation of neurosecretory cells in the segmental ganglia. Arch. Insect Biochem. Physiol. 34:391–408, 1997. Published 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Pheromonotropic stimulation of moth pheromone gland cultures in vitro

The direct neurohormonal control of pheromone biosynthesis by pheromone biosynthesis activating neuropeptide (PBAN) was demonstrated in Helicoverpa (Heliothis) spp. using pheromone gland cultures in vitro. Pheromone gland activation involved the de novo production of the main pheromone component (Z)-11-hexadecenal as revealed by radio-TLC, radio-HPLC, and radio-GC. Activation was found to be a specific response attributed to pheromone gland cultures alone. Specificity of pheromonotropic activation was demonstrated to be limited to nervous tissue extracts. A sensitive and specific radioimmunoassay was developed using [³H]-PBAN, and the spatial and temporal distribution of PBAN-immunore-activity was studied. PBAN-immunoreactivity in brain complexes was found throughout the photoperiod and in all ages. From the distribution of PBAN-immunoreactivity it appears that PBAN release is affected by photoperiod. Pheromone gland cultures were found to be competent to pheromone production irrespective of age and photoperiod. Therefore, the neuroendocrine control of pheromone production operates at the level of neuropeptide synthesis and/or release and not at the level of the target tissue itself. The involvement of cyclic-AMP as a second messenger system was demonstrated. Brain extracts and PBAN were shown to stimulate dose- and time-dependent changes in intracellular cyclic-AMP levels. The role of cyclic-AMP in this mechanism was further verified by the ability of cyclic-AMP mimetics to mimic the pheromonotropic effect of brain extracts and PBAN. However, dose-response studies using PBAN and a hexapeptide C-terminal fragment of PBAN suggested that PBAN induces a two mechanism response, one occurring at low PBAN concentrations (high affinity receptor) and another at higher PBAN concentrations (low affinity receptor). Further evidence indicating a dual receptor system was obtained with the observation that the active phorbol ester (phorbol-12-myristate 13-acetate), the diacyl-glycerol analog (1,2-dioleolyl-sn-glycerol), and the intracellular calcium ionophore (ionomycin) mimicked the physiological action of PBAN and that lithium chloride had a pheromonostatic effect. The results indicate that pheromone glands also possess receptors that are linked to inositol phosphate hydolysis. © 1994 Wiley-Liss, Inc.     

A pentapeptide of the C-terminal sequence of PBAN with pheromonotropic activity

Peptides ranging in length from 4 to 18 amino acid residues representing various sequence fragments of Helicoverpa (Heliothis)zea-pheromone biosynthesis activating neuropeptide (Hez-PBAN) were synthesized and tested for pheromonotropic activity. Biological activity resides in the C-terminus and the C-terminal pentapeptide (Phe-Ser-Pro-Arg-Leu-NH₂) represents the minimum sequence essential for induction of pheromone production. The C-terminal hexapeptide (Tyr-Phe-Ser-Pro-Arg-Leu-NH₂) had significantly higher activity at the lower doses of 100 and 10 pmol and may represent a tryptic cleavage product of PBAN.     

PBAN selective antagonists: inhibition of PBAN induced cuticular melanization and sex pheromone biosynthesis in moths

A D-Phe scan (sequential D-Phe replacement) library of linear peptides, synthesized on the basis of a slightly modified active sequence of PBAN (YFSPRL-amide) was employed to detect potential inhibitors of cuticular melanization in Spodoptera littoralis larvae and to compare their stimulatory and inhibitory melanization activity with their pheromonotropic agonistic and antagonistic activities. A quantitative melanotropic assay was used to monitor the extent of cuticular melanization elicited by Hez-PBAN1-33NH2 in S. littoralis larvae in the presence and absence of the D-Phe peptides. The data revealed the presence of two partial melanotropic antagonists, and disclosed the presence of selective pure melanotropic agonists and pure pheromonotropic antagonists indicating differences in the inhibitory and stimulatory patterns of the library with respect to both activities. The differences between the pheromonotropic and melanotropic inhibitory patterns of the peptides hints at the possibility that sex pheromone biosynthesis in the pheromone gland of Heliothis peltigera females and induction of cuticular melanization in S. littoralis may be mediated by different receptors (that may result either from presence of different receptor sub-types or may reflect species differences in receptor structure and/or properties) despite the fact that they are induced by the same peptide (PBAN1-33NH2).     

Mating Effect on Sex Pheromone Production of the Oriental tobacco budworm,Helicoverpa assulta

This study was undertaken to clarify the suppression phenomenon of sex pheromone production after mating and its relationship to the physiological mechanism in adult females of Helicoverpa assulta, and determine the mating factor from males causing depletion of sex pheromonc production. Sex pheromone production of H. assulta females was mostly terminated in 3 hours after mating. Mated females maintained with a low titer of sex pheromone until 3 days when it started to increase again, which showed a characteristic of species mating more than once. The mated female again produced pheromone upon injection of pheromone biosynthesis activating neuropeptide (PBAN) or extracts of brain-suboesophageal ganglion complexes (Br-Sg) of mated female, which were shown similar pheromonotropic activities as compared with virgin females. These results indicated that the mating did not inhibit the receptivity of pheromone gland itself and PBAN biosynthesis in suboesophageal ganglion of the mated females. And it seems to support that the depletion of sex pheromone production is responsible for blocking of PBAN release from head. To investigate the mating factor from adult males, when extracts of reproductive organs of male were injected into hemocoel of virgin females evoking depletion of sex pheromone production as shown in mated female. The results suggest that a chemical substance(s) from the male reproductive organs could be responsible for the loss of sex pheromone biosynthesis in H. assulta.     

PBAN-induced sex pheromone biosynthesis in Heliothis peltigera: Structure,dose, and time dependent analysis

A structure-activity relationship study of Hez-PBAN was performed with respect to its pheromonotropic activity, using Heliothis peltigera as the test animal. The activity of N- and C-terminally derived sequences was examined in a time- and dose-dependent mode. Using a variety of Hez-PBAN-derived fragments at two doses (1 and 10 pmol) and at different times post-injection (5–120 min), we were able to demonstrate that peptides lacking 12 and 16 amino acids from their N-terminus are as potent as the full length PBAN, and that the C-terminally derived hexapeptide was capable of stimulating sex pheromone production to a similar extent as PBAN 1–33NH₂, when its activity was analyzed at shorter post-injection times. Within the C-terminal sequence, the amide was found to play a crucial role. In addition, it was observed that the region between amino acids 9 and 13 is important for the biological activity of the full length PBAN. The fact that the pheromonotropic activity of the hexapeptide was similar to that of the full length PBAN, under specific conditions, suggests that this sequence constitutes the biologically active site of the neuropeptide. The discovery that PBAN-derived peptides reacted in a time- and dose-dependent mode, strengthens the assumption that proteolytic enzymes interfere with the pheromonotropic activity of the PBAN-derived fragments. The ability of a variety of peptides to stimulate sex pheromone biosynthesis suggests two possible mechanisms: (1) Existence of multiple pheromonotropic mechanisms which may be mediated by multiple PBAN receptors that are activated at different kinetics; (2) Existence of only one mechanism mediated by short C-terminally derived peptides. In the first case, the C-terminally derived sequences fulfill the conformational requirement of only one class of receptors, and other regions in the PBAN molecule (e.g., 9–13) fulfill the conformational requirements of a second (or other) class of receptors. In the second case, the C-terminally derived sequence is the only conformationally important sequence, and other sequences, which were found to be essential for the biological activity, serve other non-conformational purposes (e.g., protection against proteolytic degradation). © 1995 Wiley-Liss, Inc.     

Structure–function analysis of Lymantria testis ecdysiotropin: A search for the active core

A structure–function study was performed on the synthetic 21 residue neuropeptide, Lymantria testis ecdysiotropin (LTE), originally isolated from brains of Lymantria dispar pupae. The peptide induces ecdysteroid synthesis by testis sheaths of various lepidopteran species. LTE, as well as synthetic LTE 1-11, 11-21, and 11-15, stimulated synthesis in larval and pupal testes of Lymantria dispar at concentrations of 10^–9 to 10^–15 M; LTE 16-21 was weakly active, and an elongated LEU-LTE was inhibitory to synthesis at all but extremely low concentrations (10^–15M). Since the sequence and polarity of residues in LTE 1-11, 11-15, and 11-21 are quite different, several parts of the molecule must activate receptors which initiate the cascade, resulting in ecdysiogenesis in Lepidopteran testes. Arch. Insect Biochem. Physiol. 38:11–18, 1998. © 1998 Wiley-Liss, Inc.     

The effect of the juvenile hormone analog, fenoxycarb on the PBAN-receptor and pheromone production in adults of the moth Helicoverpa armigera: an "aging" hormone in adult females?

In a previous study we showed that juvenile hormone (JH) or its analog, fenoxycarb (FX), is involved in the up-regulation of pheromone biosynthesis-activating neuropeptide (PBAN) competence. JH causes induction of binding to a putative PBAN-receptor (PBAN-R) and the subsequent pheromone production by pheromone glands of pharate females. The present study demonstrates that pheromone production by the adult female is age-dependent. The pheromonotropic response increased to reach a maximum at 4 days, after which a decreased response was observed. Binding of the PBAN-R was also age-dependent. Treatment with FX inhibited both binding of PBAN to the PBAN-R and the pheromonotropic response as reflected by the production of the main pheromone component, Z-11-hexadecenal. Thus, in contrast to its up-regulatory role in pharate females, FX treatment of adult females causes down-regulation of both pheromone production and specific binding to the PBAN-R. In addition, behavioural observations showed that calling behaviour, mating success and subsequent egg-fertility are affected by treating females with FX.     

Immunochemical and biological analysis of pheromone biosynthesis activating neuropeptide in Heliothis peltigera.

This study describes the preparation and characterization of a highly specific antiserum to Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez-PBAN), and the use of this antiserum, in an enzyme linked immunosorbent assay (ELISA), to determine: a) the content of endogenous PBAN in head extracts of male and female Heliothis peltigera; b) the level of PBAN at different developmental stages; and c) the content of PBAN in four different moth species. Cross-reactivity studies revealed that the antiserum is directed mainly toward the N-terminal region of the neuropeptide, and that it exhibits similar binding affinities toward the oxidized and reduced forms of PBAN. Analysis of PBAN content in head extracts of male and female H. peltigera, at scotophase, revealed the presence of 4.97 and 4.58 pmol, respectively, in 3-day-old moths, and 5.33 and 4.78 pmol, respectively, in 7-day-old moths. The similarity in the content of PBAN at both ages and sexes was in accordance with the amount of pheromonotropic activity in these extracts which stimulated pheromone biosynthesis to a similar level. Analysis of PBAN-like immunoreactivity (IR) in head extracts of H. peltigera larvae and pupae demonstrated the existence of the neuropeptide in the 4th larval instar and continued to increase as a function of development. No IR could be detected in the first three larval instars. The larval and pupal extracts also exerted pheromonotropic activity which followed a similar pattern. The activity in these extracts, however, was considerably lower than that found in adult male and female heads. IR was also detected in head extracts of three other Noctuidae moths: Helicoverpa armigera, Cornutiplusia circumflexa and Spodoptera littoralis, indicating a high degree of chemical and structural similarity of PBAN in these moths.     

Regulation of sex pheromone biosynthesis in two noctuid species,S. littoralis and M. brassicae,may involve both PBAN and the ventral nerve cord

In order to understand better the mechanism of regulation of pheromone production in moth species, we performed ELISA analyses to detect and follow pheromone biosynthesis activating neuropeptide-like immunoreactivity (PBAN-IR) in different tissues of the two noctuidae species, Spodoptera littoralis and Mamestra brassicae. Male S. littoralis and both male and female M. brassicae brain-subesophageal ganglion (Br-SEG), corpora cardiaca-corpora allata complex, and terminal abdominal ganglion extracts showed the presence of PBAN-IR during both the photophase and the scotophase. However, PBAN-IR was found only in scotophase in female hemolymph. Analysis of extracts of Br-SEG, terminal abdominal ganglion, and hemolymph after HPLC fractionation showed that the most immunoreactive fraction in all the extracts exhibited the same retention time as Hez-PBAN, suggesting that similar PBAN-like material is present in all these tissues. In vivo studies demonstrated that severing the ventral nerve cord in M. brassicae anterior to the terminal abdominal ganglion impaired normal sex pheromone production by third-scotophase females, as was previously shown in S. littoralis. Additionally, PBAN-IR levels were lower in hemolymph samples obtained at the peak of pheromone production in both S. littoralis and M. brassicae females that had the ventral nerve cord severed compared with sham operated animals. These results, along with earlier reported data, indicate that control of pheromone production in both species may involve both PBAN (or PBAN-like peptides) and the ventral nerve cord and support the hypothesis that a neural input from the ventral nerve cord triggers the release of the pheromonotropic peptide(s) into the hemolymph, which then acts directly on the pheromone gland to stimulate pheromone biosynthesis. Arch. Insect Biochem. Physiol. 37:295–304, 1998. © 1998 Wiley-Liss, Inc.

1 We thank Germán Lázaro for insect rearing.

     

昆虫神经肽PBAN的细胞内信号转导

昆虫性信息素多数为长链的不饱和醇、醋酸酯、醛或酮类,链长一般为10-20碳,主要在性信息素腺体内由乙酰辅酶A经过脂肪酸合成、碳链缩短、去饱和以及碳酰基的还原修饰等步骤合成的;而性信息素合成激活肽(pheromone biosynthesis activating neuropeptide,PBAN)是由昆虫食管下神经节中的部分神经细胞合成和分泌的神经肽,通常由33个氨基酸组成,在C-末端有一个相同的五肽序列,主要调控性信息素的生物合成。有关PBAN的细胞内信号转导是近几年的研究热点,研究显示 PBAN首先与性信息素腺体细胞表面的G蛋白偶联受体结合,随后依据昆虫种类的不同,其细胞内信号转导方式主要有三种:(1)以cAMP信号传导途径进行信号转导;(2)以cAMP和磷脂酰肌醇信号传导途径共同进行信号转导;(3)主要以Ca2 为第二信使进行信号传导。