Nutritional status modulates behavioural and olfactory bulb Fos responses to isoamyl acetate or food odour in rats: roles of orexins and leptin.

Food odours are major determinants for food choice, and their detection depends on nutritional status. The effects of different odour stimuli on both behavioural responses (locomotor activity and sniffing) and Fos induction in olfactory bulbs (OB) were studied in satiated or 48-h fasted rats. We focused on two odour stimuli: isoamyl acetate (ISO), as a neutral stimulus either unknown or familiar, and food pellet odour, that were presented to quiet rats during the light phase of the day. We found significant effects of nutritional status and odour stimulus on both behavioural and OB responses. The locomotor activity induced by odour stimuli was always more marked in fasted than in satiated rats, and food odour induced increased sniffing activity only in fasted rats. Fos expression was quantified in periglomerular, mitral and granular OB cell layers. As a new odour, ISO induced a significant increase in Fos expression in all OB layers, similar in fasted and satiated rats. Significant OB responses to familiar odours were only observed in fasted rats. Among the numerous peptides shown to vary after 48 h of fasting, we focused on orexins (for which immunoreactive fibres are present in the OB) and leptin, as a peripheral hormone linked to adiposity, and tested their effects of food odour. The administration of orexin A in satiated animals partially mimicked fasting, since food odour increased OB Fos responses, but did not induce sniffing. The treatment of fasted animals with either an orexin receptors antagonist (ACT-078573) or leptin significantly decreased both locomotor activity, time spent sniffing food odour and OB Fos induction in all cell layers, thus mimicking a satiated status. We conclude that orexins and leptin are some of the factors that can modify behavioural and OB Fos responses to a familiar food odour.

Small intensely fluorescent cells of the rat paracervical ganglion synthesize adrenaline, receive afferent innervation from postganglionic cholinergic neurones, and contain muscarinic receptors.

In the paracervical ganglion (PCG) of the rat, double-labelling immunofluorescence for catecholamine-synthesizing enzymes and HPLC measurement of catecholamine contents were first performed to evaluate whether intraganglionic small intensely fluorescent (SIF) cells are capable of synthesizing adrenaline. Immunolabelling for tyrosine hydroxylase (TH), dopamine beta-hydroxylase and phenylethanolamine-N-methyl transferase (PNMT) occurred in all SIF cells of the PCG, thus demonstrating the presence of all the enzymes required for adrenaline biosynthesis. Adrenaline levels were undetectable in the PCG but to test the hypothesis that PNMT is active in SIF cells, catecholamines were measured in ganglia of rats pretreated with pargyline, an inhibitor of the monoamine oxidase, the major enzyme involved in the catecholamine degradation. Pargyline treatment increased adrenaline levels in the PCG, thus demonstrating that SIF cells are capable of adrenaline synthesis. The undetectable levels of adrenaline in the PCG of untreated rats suggested a slow rate of biosynthesis of adrenaline in the ganglion. Furthermore, the use of double-labelling showed that SIF cells of the PCG were stained for muscarinic receptors and were approached by varicose ChAT-immunoreactive nerve fibres. Nerve fibres immunoreactive for ChAT were also observed associated with nerve cell bodies of ganglion neurones. Following deafferentation of the PCG, the ChAT-immunoreactive nerve fibres surrounding nerve cell bodies totally disappeared indicating their preganglionic origin, while those associated with SIF cells did not degenerate, which demonstrate that they derived from intraganglionic cholinergic neurones. Taken together, the results show that adrenaline may be a transmitter for SIF cells in the PCG and suggest that cholinergic neurones of the parasympathetic division of the PCG can modulate the SIF cell activity through the activation of muscarinic receptors.

Sympathetic innervation of the upper and lower regions of the uterus and cervix in the rat have different origins and routes.

The origins and routes of the postganglionic sympathetic nerve supply to the upper and lower uterus and to the cervix were investigated in the rat by using denervation procedures combined with immunohistochemistry and retrograde tracing. The sympathetic nerve fibers of the upper part of the uterus arise from the ovarian plexus nerve. They mainly originate (90%) from neurons of the suprarenal ganglia (SRG) and of the T10 to L3 ganglia of the paravertebral sympathetic chain. Fluoro-Gold injections into different regions of the upper uterus showed that the SRG neurons mainly provide innervation to the tubal extremity (52%) rather than to the uterine portion below this area (26%). Very few neurons of the celiac ganglion or the aorticorenal ganglia participated in this innervation. Most of the sympathetic innervation of the lower uterus and the cervix (90%) originates from neurons of the paravertebral ganglia T13 to S2, principally at the L2-L4 levels. By using immunocytochemistry, we show that very few tyrosine hydroxylase-positive neurons of the pelvic plexus project to these areas, where they represent only 3% of the sympathetic nerve supply. Again, very few neurons of the inferior mesenteric ganglion (IMG) supply the lower uterus and the cervix. The comparison between retrograde tracing experiments in intact animals and after the removal of the IMG shows that very few sympathetic postganglionic axons from the paravertebral chain pass through the IMG to reach the lower uterus and the cervix. In contrast, these axons mainly project to splanchnic nerves bypassing the IMG to connect with the hypogastric nerves. In addition, some axons supplying the lower uterus follow the superior vesical arteries and then reach the organ. Taken together, these results show that the upper region of the uterus receives a sympathetic innervation that is different in origin and route from that of the lower uterus and the cervix. Such a marked region-specific innervation suggests that nerve control of the myometrial activity may be functionally different between the oviduct and the cervical ends of the uterus.

Involvement of the pelvic plexus and the suprarenal ganglia in the neuropeptide Y (NPY) innervation of the cervix and the uterus of the rat.

The involvement of the pelvic plexus and suprarenal ganglia in the neuropeptide Y (NPY) innervation of the genital tract was studied in the female rat by means of denervation experiments and retrograde tracing studies. Removal of the paracervical ganglia caused a significant decrease of the NPY-immunoreactive nerve density and NPY concentration in the lower part of the genital tract: cervix, uterine body and lower part of the uterine horn. The decrease in NPY concentration in these three regions was more pronounced after lesion of the pelvic plexus. Lesion of the ovarian nerve plexus caused a depletion in the NPY-immunoreactive nerve fibres and a decrease in NPY concentration in the upper part of the uterine horn. Pelvic nerve section, inferior mesenteric ganglia excision and superior ovarian nerve section had no effect on the NPY innervation in the genital tract. Injection of fluorogold into the cervix and lower part of the uterus combined with immunohistochemistry revealed that 87.5% of labelled neurons in the pelvic plexus were NPY-immunoreactive. Following injection of fluorogold into the upper part of the uterus, 92% of labelled neurons in the suprarenal ganglia were NPY-immunoreactive. Treatment with 6-hydroxydopamine revealed that the NPY-immunoreactive nerve fibres were non-noradrenergic in the cervix, but were noradrenergic in the upper part of the uterus. In the uterine body and lower part of the uterine horn, both noradrenergic and non-noradrenergic NPY-immunoreactive nerve fibres were observed. These data demonstrate the major contribution of pelvic plexus neurons in the non-noradrenergic NPY innervation of the lower part of the genital tract, and the involvement of the suprarenal ganglia in the noradrenergic NPY innervation of the upper part of the uterus via the ovarian nerve plexus.

Distribution of noradrenergic neurons in the female rat pelvic plexus and involvement in the genital tract innervation.

The involvement of the pelvic plexus noradrenergic neurons in the innervation of the genital tract was studied in the female rat. Several small ganglia were observed in addition to the paracervical ganglion and immunocytochemistry for tyrosine hydroxylase was performed to examine the distribution and number of the noradrenergic neurons. 5069 +/- 1525 nerve cell bodies were counted in the paracervical ganglion and 9.0 +/- 0.8% of them were noradrenergic, displaying a clear somatotopic distribution in the ventro-medial part of the ganglion. Some accessory ganglia were located ventral to the main paracervical ganglion. 414 +/- 149 nerve cell bodies were found in the accessory ganglia, of which 20.4 +/- 3.1% were noradrenergic. Ganglia along the vesical branch of the hypogastric nerve, referred to as an hypogastric plexus, contained 233 +/- 83 neurons among which 12.7 +/- 7.2% were noradrenergic. Bilateral removal of the pelvic plexus produced degeneration of all the tyrosine hydroxylase-immunoreactive nerve fibres in the lower part of the uterus and in the cervix. In contrast, excision of the paracervical ganglia and the accessory ganglia caused no significant change in this innervation pattern. Combined retrograde tracing study and immunocytochemistry for tyrosine hydroxylase revealed a very small number of noradrenergic neurons also labelled with fluoro-Gold. Both findings suggest a limited involvement of the pelvic plexus noradrenergic neurons in the innervation of the lower genital tract.

Proprioceptive activity in primate primary somatosensory cortex during active arm reaching movements.

1. We studied the activity of 254 cells in the primary somatosensory cortex (SI) responding to inputs from peripheral proprioceptors in a variety of tasks requiring active reaching movements of the contralateral arm. 2. The majority of cells with receptive fields on the proximal arm (shoulder and elbow) were broadly and unimodally tuned for movement direction, often with approximately sinusoidal tuning curves similar to those seen in motor and parietal cortex. 3. The predominant temporal response profiles were directionally tuned phasic bursts during movement and tonic activity that varied with different arm postures. 4. Most cells showed both phasic and tonic response components to differing degrees, and the population formed a continuum from purely phasic to purely tonic cells with no evidence of separate distinct phasic and tonic populations. This indicates that the initial cortical neuronal correlates of the introspectively distinguishable sensations of movement and position are represented in an overlapping or distributed manner in SI. 5. The directional tuning of the phasic and tonic response components of most cells was generally similar, although rarely identical. 6. We tested 62 cells during similar active and passive arm movements. Many cells showed large differences in their responses in the two conditions, presumably due to changes in peripheral receptor discharge during active muscle contractions. 7. We tested 86 cells in a convergent movement task in which monkeys made reaching movements to a single central target from eight peripheral starting positions. A majority of the cells (46 of 86, 53.5%) showed a movement direction-related hysteresis in which their tonic activity after movement to the central target varied with the direction by which the arm moved to the target. The directionality of this hysteresis was coupled with the movement-related directional tuning of the cells. 8. We recorded the discharge of 93 cells as the monkeys performed the task while compensating for loads in different directions. The large majority of cells showed a statistically significant modulation of activity as a function of load direction, which was qualitatively similar to that seen in motor cortex under similar task conditions. Quantitatively, however, the sensitivity of SI proprioceptive cells to loads was less than that seen in motor cortex but greater than in parietal cortex. 9. We interpret these results in terms of their implications for the central representation of the spatiotemporal form ("kinematics") of arm movements and postures. Most importantly, the results emphasize the important influence of muscle contractile activity on the central proprioceptive representation of active movements.

Tactile activity in primate primary somatosensory cortex during active arm movements: correlation with receptive field properties.

1. Five hundred ninety-five single neurons with tactile receptive fields (RFs) on the contralateral arm were isolated in the primary somatosensory cortex (SI) of awake, behaving monkeys. 2. Fifty-eight percent of the tactile cells showed significantly different levels of activity during active movements of the arm in eight directions or during active maintenance of the arm over the target endpoints. 3. The discharge of many of the active tactile cells was unimodally tuned with movement direction and the pattern of the tactile population activity varied in a meaningful fashion with arm movement direction and posture. 4. The intensity of the arm-movement-induced activity was typically less than that evoked by direct tactile stimulation of the cell's RF. 5. The probability of task-related activity was correlated with certain RF properties, in particular the sensitivity of the cell to lateral stretch of the skin and to passive arm movements that avoided direct contact of the RF on any surface. 6. This suggests that task-related activity results mainly from the activation of tactile receptors by mechanical deformation of the skin as the arm changes geometry during movement. 7. These results demonstrate that tactile activity containing potential proprioceptive information is generated in SI during active arm movements that avoid direct contact of the skin with external surfaces. Whether or not this input contributes to the kinesthetic sensations evoked by the movements cannot be resolved by this study.

Tactile activity in primate primary somatosensory cortex during active arm movements: cytoarchitectonic distribution.

1. Cells were recorded in areas 3b and 1 of the primary somatosensory cortex (SI) of three monkeys during active arm movements. Successful reconstructions were made of 46 microelectrode penetrations, and 298 cells with tactile receptive fields (RFs) were located as to cytoarchitectonic area, lamina, or both. 2. Area 3b contained a greater proportion of cells with slowly adapting responses to tactile stimuli and fewer cells with deep modality inputs than did area 1. Area 3b also showed a greater level of movement-related modulation in tactile activity than area 1. Other cell properties were equally distributed in the two areas. 3. The distribution of cells with low-threshold tactile RFs that also responded to lateral stretch of the skin or to passive arm movements was skewed toward deeper laminae than for tactile cells that did not respond to those manipulations. 4. The variation of activity of tactile neurons during arm movements in different directions was weaker in the superficial laminae than in deeper cortical laminae. 5. Cells with only increases in activity during arm movements were preferentially but not exclusively located in middle and superficial layers. Cells with reciprocal responses were found mainly in laminae III and V, whereas cells with only decreases in activity were concentrated in lamina V. 6. Overall, active arm movements evoke directionally tuned tactile and "deep" activity in areas 3b and 1, in particular in the deeper cortical laminae that are the source of the descending output pathways from SI.

Effect of alpha-adrenergic blocking agents on uterine activity in the ewe at the end of gestation.

The electromyographic activity (EMG) of the uterus was recorded in vivo in 8 unanaesthetized ewes from the 140th day of gestation up to parturition. The effects on uterine activity of treatments with an alpha 1-receptor blocker (prazosin) and an alpha 2-receptor blocker (yohimbine) were studied. During the last days of gestation, EMG activity consisted of periodic active phases (1-2/h). During the last 16-17 hours, uterine activity increased sharply; this period was referred to a labour. Intravenous perfusion of prazosin (0.03 mg/kg/mn over 1 h) or intravenous injections (1 mg/kg) did not modify uterine activity either before or during labour. Intravenous perfusion of yohimbine (0.03 mg/kg/mn during 1h) inhibited uterine activity before and during labour. In all cases, lambing occurred between the 142nd and 145th day of gestation, which corresponds to the normal lambing period. These results suggest that, in the ewe, uterine alpha 2-receptors are important for normal uterine activity at the end of gestation and in. parturition.

Peridural anesthesia disturbs maternal behavior in primiparous and multiparous parturient ewes.

Several experiments were carried out to study the effects of peridural anesthesia (Sylvocaine, 6 ml between sacrum and 1st caudal vertebra) performed either at the first signs of birth (early peridural: EP), or little before expulsion (late peridural: LP). When performed late, peridural anesthesia altered maternal behavior only slightly when compared with controls. By contrast severe deficits were observed in the case of EP. Seven out of 8 primiparae failed to show interest for their lamb within 30 min of the birth of the young (vs. 1/9 in LP group, p less than 0.01). In multiparae these proportions were 8/27 and 0/22 respectively (p less than 0.01). Within the EP group the effects of the peridural were more marked in primiparous than in multiparous mothers (p less than 0.05). Even in EP multiparous ewes becoming maternal within 5 min after giving birth a reduction in duration of licking was noted, when compared with the LP group (p less than 0.05). On the other hand, these same ewes established normally a selective bond within 2 hours after giving birth, as did the LP or control ewes. These results confirm the importance of genital stimulation for the rapid onset of maternal behavior in parturient ewes. They failed however to clarify the role played by genital stimulation in the establishment of a selective maternal bond.

Uterine motor responses to an alpha-adrenergic agonist (phenylephrine) in the ewe during oestrus and at the end of gestation.

The alpha-adrenergic activity of the myometrium was studied by recording the electromyographic activity (EMG) of the uterus in 4 conscious cyclic ewes during oestrus and in 8 conscious pregnant ewes during the last 6 days of gestation. In the cyclic ewes, changes in intra-uterine pressure were recorded at the same time as the EMG. Motor responses to perfusions of phenylephrine, a specific alpha-adrenergic agonist, were studied at three uterine sites. In the ewes in oestrus, uterine activity was stimulated at the three sites by perfusions with phenylephrine (0.6, 2.5, 5 or 10 micrograms/kg/min). The whole uterine horn was alpha-adrenergic-responsive. The effect of the drug was dose-dependent in that the uterine response increased with the dose and reached a plateau at 5 micrograms/kg/min. In the late pregnant ewes, the motor responses to the perfusion of phenylephrine at 10 micrograms/kg/min were studied at three uterine sites once a day during the last 6 days of gestation. Plasma levels of progesterone and total oestrogens were measured at the same time. Up to 48 h before parturition, the effect of phenylephrine depended on the uterine site. The drug had no or little effect at the tubal end of the horn. Phenylephrine stimulated uterine activity at the cervical end of the horn in at least 50% of the ewes. Thus, during this part of gestation, the alpha-adrenergic sensitivity of the myometrium was greater at the cervical than at the tubal end of the uterine horn. Forty-eight hours before parturition, phenylephrine stimulated uterine activity at all three uterine sites in all the ewes. Thus, alpha-adrenergic sensitivity developed over the uterine horn beginning 48 h before parturition at the same time that the oestrogen level increased.

[Uterine motor responses to catecholamines in the ewe under different steroidal impregnations. Demonstration of the role of endogenous catecholamines]. / Etude des réponses motrices de l'utérus aux catécholamines chez la brebis sous différentes impregnations stéroïdiennes. Mise en évidence du rôle des catécholamines endogènes.

The electromyographic activity (EMG) of the uterus was recorded in vivo in 6 conscious ovariectomized ewes treated with oestrogen. In 6 cyclic ewes, changes in intrauterine pressure were recorded at the same time as the EMG. Motor responses to noradrenaline, isoprenaline and adrenaline injections were studied at 3 uterine sites in the ovariectomized ewes. Uterine activity was stimulated by noradrenaline and inhibited by isoprenaline, providing evidence that there were both alpha and beta-adrenergic receptors in the myometrium of the oestrogen-treated ovariectomized ewes. Adrenaline caused an increase of myometrial activity at the cervical end and the middle of the uterine horn, demonstrating that alpha-receptors were predominant. Adrenaline had little effect on activity at the tubal end of the horn, but after the administration of propranolol, a blocker of beta-adrenergic receptors, there was a stimulatory effect. These results show that the alpha-receptor/beta-receptors, there was a stimulatory effect. These results show that the alpha-receptor/beta-receptor ratio along the uterine horn was not constant. In cyclic ewes, the effects of noradrenaline and adrenaline in the middle of the uterine horn were stimulatory during oestrus and luteal phase, indicating that alpha-receptors were predominant in that region under both oestrogenic and progesteronic dominance. The perfusion of phentolamine, a blocker of alpha-adrenergic receptors, into ovariectomized ewes treated with oestrogen provided evidence that endogenous catecholamines modulate uterine activity.

[Electromyographic activity of the uterus in the ewe during the sexual season: comparison of natural estrus and estrus induced by progestagens alone or with PMSG supplementation]. / Activité électromyographique de l'utérus chez la brebis pendant la saison sexuelle: comparaison de l'oestrus naturel et de l'oestrus induit par les progestagènes seuls ou avec une supplémentation de PMSG.

Electromyographic (EMG) activity of the uterus was recorded in vivo in 3 groups of ewes in oestrus during the breeding season. The ewes were either in natural oestrus or in oestrus induced by progestagens with or without PMSG supplementation. Plasma concentrations of LH were measured at regular intervals in order to determine the onset of the preovulatory surge of LH (To). During natural oestrus, the uterus exhibited a spontaneous rhythmic activity composed of bursts of potentials. Burst frequency was maximal at the moment of preovulatory LH release, then decreased. Percentages of downward, upward and non-definite propagations were calculated during 1-h periods at the beginning of the LH peak and 6, 12, 24 and 36 h afterwards. There was no difference between the relative proportions of these types of propagation at any of the times analysed. Mean burst frequency was not modified by progestagen pre-treatment but showed more interanimal variability at the moment of maximal frequency in ewes treated with progestagen. For the first 12 h after To, the organization of uterine activity was not modified by progestagens but non-definite propagation became predominant 24 and 36 h after To, namely from the time of ovulation onward. PMSG increased burst frequency. The increase of frequency variability between animals, normally observed at the beginning of oestrus, and the predominance of non-definite propagation, normally observed at the end of progestagen-induced oestrus, did not appear when the ewes had been treated with PMSG.

The effect of relaxin on in vivo uterine electromyographic activity in the conscious ovariectomized ewe is oestrogen-dependent.

Electromyographic (EMG) activity of the uterus was recorded in vivo in 4 conscious ovariectomized ewes treated with oestrogen (one injection of 100 micrograms of oestradiol benzoate). Doses of 500 micrograms of purified porcine relaxin were injected intravenously 12, 16, 20, 24, 28 and 32 hrs after oestrogen treatment. Relaxin had an inhibitory effect on uterine activity between 16 and 32 hrs after oestrogen treatment. Because the period during which relaxin had a biological effect corresponded to the moment when oestrogen-induced uterine activity was maximal, it is suggested that the ability of relaxin to inhibit uterine activity in the ewe is oestrogen-dependent.

[Study of uterine motor responses to vaginal and uterine stimulations in the ewe in estrus]. / Etude des réponses motrices de l'utérus aux stimulations vaginales et utérines chez la Brebis en oestrus.

We recorded in vivo the electromyographic (EMG) activity of the myometrium in 36 conscious ewes, including ovariectomized animals treated with oestrogen and cyclic animals in oestrus. We studied the motor responses of the uterus to distension of the vagina with a speculum and distension of the uterine horn with a balloon. These two types of stimulation provoked an increase in myometrial activity. By comparing the responses before and after hypophysectomy and before and after treatment with an alpha-adrenergic blocking agent, we were able to evaluate the nature of these responses. Vaginal stimulation induced two types of response: 1) a response of long duration, possibly the result of a spinal reflex followed by a reflex release of oxytocin; 2) a response of short duration, probably resulting simply from a spinal reflex whose efferent pathway is composed of sympathetic fibres. Uterine stimulation activated motility in the stimulated horn only. Thus, the observed increase in EMG activity was not a reflex but the response of the uterine muscle to its own distension.

Effect of an inhibitor of prostaglandin synthesis on uterine motility in the ovariectomized ewe during induced oestrus. A preliminary report.

The myometrial electromyographic activity (EMG) of three ovariectomized ewes was studied after two consecutive treatments used for inducing oestrus: oestrogen administration and oestrogen plus an inhibitor of prostaglandin synthesis (indomethacin). The myometrial activity preceding treatments was used as a reference. The results of this study demonstrated that indomethacin modified the EMG of the myometrium recorded 24 hours after oestrogen injection. The rhythmic activity normally induced by oestrogens was suppressed, so that there was little or no difference between uterine activity recorded before and 24 hours after oestrogen injection.

[Electromyographic study of uterine motility in the ewe. Action of hormones]. / Etude électromyographique de la motricité de l'utérus chez la brebis. Action des hormones

PIP: Electrical and mechanical activity of the myometrium was recorded in 46 ewes, including both cyclic animals and ovariectomized animals treated with estrogen or progesterone. In ovariectomized ewes, estrogen induces rhythmic electromyographic activity composed of bursts of action potentials related to variations in intra uterine pressure. Maximum EMG activity occurs 24-36 hours after treatment with estradiol benzoate, the beginning of estrus. After estrogen treatment, low doses of oxytocin provoke a continuous discharge of action potentials, while high doses abolish them. After progesterone treatment, uterine EMG activity is composed of slower variations in potential unrelated to myometrial contractions. In cyclic ewes during estrus the uterus exhibits spontaneous rhythmic EMG activity, identical with that induced by estrogen in the ovariectomized animal. This activity, characterized by bursts of action potentials, is confined to the last day of the cycle and the first 3 days of the following cycle, except in a few ewes which showed spontaneous activity on the 6th day. In the conscious ewe, ovariectomized and estrogen-treated or intact at the beginning of estrus, vaginal stimulation induces a marked increase in myometrial electrical activity; no such effect is produced in the anesthetized animal.^ieng