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The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is one of the most injurious pest at global level. During the last years, several electrophysiological and behavioural studies have been carried out in order to investigate plant volatile compound-insect interactions with the aim to use this knowledge in sustainable control techniques. It has been observed that lemons are not attacked by medfly, probably because of the peel oil, that is toxic to other fruit flies. In the present paper electrophysiological recordings were conducted to evaluate the insect sensitivity to peel extract and peel oil of two Sicilian cultivars (Interdonato and Lunario) of Citrus x limon (L.) Burm.f. on C. capitata females. Behavioural bioassays were also performed to show their possible biological activity (repellent, antioviposition, insecticidal). C. limon peel extracts in different solvents (petroleum ether, dichloromethane and methanol) were investigated at various concentrations using a single cell recording technique (stimulation of tarsal taste chemosensilla). Different tarsal taste cell responses to the two cultivars were recorded. The higher sensitivity was evoked by C. limon Interdonato, particularly to the methanol extract, which elicited significant increases in the spike frequency at increasing concentrations. The peel oil of the same cultivars as well as that ones of other two C. limon varieties (Monachello and Femminello) have been tested by EAG techniques. The EAG data showed a high sensitivity (about -8.0/8.5mV) of the medfly antennae to the oils of Citrus spp. and a clear dose-response relationship. Responses of adult females (virgin and mated) to Citrus spp. peel extract were quantified in a double-choice test using yellow spheres (diameter 7.0cm) housed in field cages. Preliminary tests conducted on three extracts of C. limon Interdonato and Lunario have provided interesting results. It was recorded a general decrease of the oviposition on treated spheres compared to control and in the case of the cultivar Lunario, a mortality of insects.

La mosca mediterranea della frutta, Ceratitis capitata (Wiedemann) (Diptera Tephritidae) è uno degli insetti maggiormente dannosi a livello mondiale. In anni recenti sono state condotte numerose ricerche sui semiochimici coinvolti nelle interazioni insetto-pianta ospite, avvalendosi di studi elettrofisiologici e comportamentali, con lo scopo di utilizzare le sostanze biologicamente attive eventualmente identificate in strategie di controllo innovative e sostenibili. È noto che i limoni non sono attaccati da C. capitata, molto probabilmente a causa degli oli essenziali dell’epicarpo, tossici per altre mosche della frutta. Nel presente lavoro sono state effettuate registrazioni elettrofisiologiche per valutare la sensibilità delle femmine di C. capitata ad estratti ed oli della buccia di due varietà coltivate (cv.) siciliane (Interdonato, Lunario) di Citrus limon Burm. Sono stati condotti, inoltre, biosaggi comportamentali per studiarne l’eventuale attività biologica. La percezione degli estratti dell’epicarpo (in etere di petrolio, diclorometano e metanolo) è stata studiata, a varie concentrazioni, utilizzando una tecnica di registrazione da singola cellula (SCR), stimolando i sensilli tarsali del gusto di C. capitata. Sono state registrate le risposte di diversi tipi di cellule gustative. La stimolazione più intensa è stata indotta dagli estratti della cv. Interdonato, in particolare dall’estratto metanolico, con incrementi significativi della frequenza dei potenziali di azione al crescere della dose. La percezione dei composti volatili degli oli essenziali estratti dalle stesse cv, oltre a quelli di altre due cvv. di limone (Monachello, Femminello), è stata indagata mediante tecnica elettroantennografica (EAG). I dati EAG hanno evidenziato un’elevata sensibilità (ca. 8.5 mV) delle antenne di C. capitata ed una netta correlazione dose-risposta. Le risposte comportamentali delle femmine (vergini ed accoppiate) agli estratti dell’epicarpo sono state studiate mediante un biosaggio a doppia scelta, utilizzando sfere di colore giallo (diametro 7.0 cm) posizionate in un’apposita gabbietta. Le prove preliminari condotte con tre estratti delle cvv. Interdonato e Lunario hanno fornito risultati molto promettenti. È stata registrata, infatti, una diminuzione generalizzata dell’ovideposizione sulle sfere trattate rispetto al controllo

Experiments were performed on normotensive rats exposed to vitamin D deficient and control diets from the 22nd to the 180th day of age. In 60-120- and 180-day-old rats. The following parameters were evaluated: a) The vasomotor responses elicited by receptor agonists in the absence and in the presence of the respective antagonists [L-norepinephrine (NE) before and 5 min after prazosin; L-isoprenaline (I) before and 5 min after DL-propranolol; L-dopamine (DA) before and 5 min after L-sulpiride or SCH 23390 or chlorpromazine; acetylcholine (Ach) before and 5 min after atropine; histamine (H) before and after chlorpheniramine; 5-hydroxytryptamine (5-HT) before and 5 min after methysergide or ketanserin]; by carotid-sinus baroreceptor stimulation (CO) before and 5 min after hexamethonium, and by electrical stimulation of the vagus peripheral head (V) before and after atropine; b) Reflex tachycardia elicited by bilateral carotid occlusion (CO) (for 40 sec) and by sodium nitroprusside; c) Catecholamine (norepinephrine, epinephrine) and arginine-vasopressin plasma levels; d) Cholesterol, triglyceride and electrolyte (Na+, K+, Cl-, Ca2+) serum levels. Our results showed that vitamin D deficient diets induced a decrease in pressor responses to NE and CO, and an increase in hypotensive responses to I, DA, Ach, H, 5-HT and V. Changes of arterial blood pressure, heart rate, catecholamine and arginine-vasopressin plasma levels were not observed. Cholesterol, triglyceride and electrolyte (Na+, K+, Cl-) serum levels were not modified, while Ca2+ serum levels decreased. In conclusion, our data suggest that vitamin D depletion can induce changes of pressor and depressor vasomotor responses and suppose a direct role for vitamin D in regulating vasomotor reactivity.

The synthesis of 1,3,3-trimethyl-N-[(2-pyridyl)methyl]-2- oxabicyclo [2.2.2]octan-6-amine (II) (exo, endo mixture) starting from 1,3,3-trimethyl-N-nitro-2-oxabicyclo [2.2.2]octan-6-imine (I), as well as of a series of amides (III) derived from the above amine, is described. Some compounds (III) showed remarkable depressant and antiarrhythmic activities in rats and mice, respectively, whereas the clofibric acid amide (III e) showed an appreciable hypolipidemic activity in rats. Moreover, the above compounds usually exhibited a moderate infiltration anesthesia in mice, as well as a weak hypotensive and bradycardic activity in rats.