Biomedical subjects

J Cipolla-Neto

Publications and source records attributed to J Cipolla-Neto.

31 records · Page 2Linked to original sources

PubMed1993

Circadian variations of superoxide dismutase activity in the rat pineal gland.

The 24 h profile of the activity of the antioxidant enzyme superoxide dismutase (SOD) in the pineal gland of rats was studied. Rhythmic analysis showed a significant 24 h rhythm with an amplitude of oscillation of 25% of the 24 h mean value, that was 100.34 +/- 1.6 U SOD (nitrite). An ultradian rhythm of 9 h was also detected. The diurnal profile of superoxide dismutase activity is discussed in relation to the oxidative metabolism of the pineal gland.

Activity Cycles↗

PubMed1993

Age-related changes in melatonin modulation of sympathetic neurotransmission.

An age-related reduction in the maximal acetylcholine (ACh)-induced contraction in the prostatic portion of rat vas deferens during the day was observed. This contraction is due to the release of norepinephrine and adenosine triphosphate from sympathetic nerve terminals. Male Wistar rats (4 and 24 months-old) were housed on a light/dark cycle (12:00 h/12:00 h, lights on at 6:00). The diurnal variation of ACh-induced contraction was determined on animals sacrificed every 3 h during the day. Aging reduced the maximal contraction and shortened the length of the nocturnal response. In both young and old rats, the response to ACh increased at 21:00, but it remained elevated until 12:00 in young rats and until 24:00 in old rats. Both nocturnal administration of melatonin for 2 consecutive days (9 mg/kg/day, s.c.) and melatonin incubation (100 pg/ml, 4 h) of the vas deferens from old rats sacrificed at 15:00 h significantly potentiated the ACh-induced contraction. However, this potentiation was smaller than that observed in young rats. The results presented here show the loss of maximal contractile response to ACh with age and a qualitative change in the rhythm characteristics of this phenomenon. Moreover, the age-related decrease in the ACh-induced contraction in the prostatic portion of the rat vas deferens is dependent not only on a reduction in the plasma nocturnal increase of melatonin concentration but also on a lower responsiveness of short sympathetic neurons to melatonin.

Acetylcholine↗

PubMed1991

Diurnal variation of the rat vas deferens contraction induced by stimulation of presynaptic nicotinic receptors and pineal function.

A rhythmic variation of maximal contraction induced by acetylcholine in the prostatic portion of rat vas deferens was tested. This contraction is due to the release of norepinephrine and ATP from sympathetic nerve terminals. Male Wistar rats (4 months old) were housed on a light/dark cycle (12 hr/12 hr, lights on at 6:00 A.M.). The diurnal variation of acetylcholine-induced contraction was determined on animals sacrificed every 3 hr during the day. The maximal contractile response shows a circadian (24:00 hr) and an ultradian (12:20 hr) rhythm. Otherwise, the sensitivity to acetylcholine (pD2 values) and the maximal contraction or pD2 values to norepinephrine, ATP and K+ did not change throughout the day. The blocking effect of hexamethonium on the contraction induced by field stimulation was higher at 9:00 P.M. than at 3:00 P.M., indicating a diurnal variation of the effect of endogenous released acetylcholine. When melatonin released by the pineal gland is suppressed by constant illumination or superior cervical ganglionectomy, the circadian rhythm was abolished and the period of the ultradian rhythm changed to 6:30 hr. The acetylcholine-induced contraction of vasa deferentia from animals sacrificed at 3:00 P.M. and incubated "in vitro" with melatonin (100 pg/ml) increased reaching nocturnal values. In conclusion, it seems that a functional pineal gland, most probably through the synthesis and release of melatonin, is necessary for expression (circadian) and modulation (ultradian) of the rhythmicity in the maximal acetylcholine-induced contraction in the prostatic portion of the rat vas deferens.

Acetylcholine↗

PubMed1989

Biological aspects and self-evaluation of shiftwork adaptation.

Two male truck drivers working in a Brazilian cellulose plant and classifying themselves as "well-" and "ill-adapted" to a shiftwork schedule of 4 days-on and 1 day-off, participated in an autorhythmometric study. Psychophysiological self-ratings (calmness, stress and alertness), oral temperature measurements and urine collections (detection of K+,Na+ and 17-OH concentrations) were performed regularly during the waking period for 15 consecutive days during the shift schedule--the midday shift (11:00 to 19:00 h), early-morning shift (03:00 to 11:00 h) and evening shift (18:00 to 02:00 h), including days-off. Cosine fitting of the data to a successive running one-day window revealed different individual temporal patterns, with the "well-adapted" subject showing a relatively stable phase relationship of the variables under study and the "ill-adapted" subject showing a less stable relationship. The different patterns could explain, at least partially, the fact that one subject feels "adapted" to shiftwork and the other not.

Adaptation, Physiological↗

PubMed1988

Remarkable similarities between the temporal organization of neocortical electrographic sleep patterns of rats and humans.

Electrocorticographic activity was automatically recorded in albino rats for 72 consecutive h and analyzed by procedures suitable to detect 24-h rhythms. Beta (alert wakefulness), theta (somnolence), delta (slow wave sleep) and sigma 1 (superficial synchronized sleep) activities showed a robust circadian rhythmic distribution. The acrophases (maxima of the adjusted cosine curve) occurred at 23:39, 07:59, 08:37 and 13:25 h, respectively. EMG atonia and extreme hypotonia (less than 10% of mean EMG level) episodes showed a 24-h rhythm peaking at 14:18 h. The temporal sequence within the circadian rest period, i.e., somnolence, slow wave sleep, superficial synchronized sleep and paradoxical sleep, is very similar to that known to occur during the nocturnal sleep of humans.

Animals↗

PubMed1988

Lack of similarity between the effect of lesions of the suprachiasmatic nucleus and subparaventricular hypothalamic zone on behavioral circadian rhythms.

Rats were submitted to electrolytic lesion of either the suprachiasmatic nucleus (SCN) or the subparaventricular hypothalamic zone (SPVH) and the effects on circadian behavioral rhythms were compared. While the SCN lesion abolished the circadian rhythmicity of all behavioral patterns, the SPVH lesion only abolished that of the eating and drinking behavior and reduced the amplitude of a behavioral item usually associated with REM sleep.

Animals↗

PubMed1983

Imprinting in the domestic chick: the role of each side of the hyperstriatum ventrale in acquisition and retention.

Previous experiments have shown that the acquisition of a preference through imprinting is impaired if part (IMHV) of the hyperstriatum ventrale is destroyed bilaterally before chicks are exposed to a visually conspicuous (training) object. The present experiments were undertaken to determine (i) whether the acquisition of a preference for the training object is possible with only one IMHV intact and, if acquisition is possible, (ii) whether destruction of this IMHV impairs retention. Chicks were hatched and reared in darkness to congruent to 12 h posthatch. The chicks were then anaesthetised and a lesion placed in (i) the left IMHV (N = 12 chicks), (ii) the right IMHV (N = 12), (iii) the left hyperstriatum accessorium (HA) (N = 12) or (iv) the right HA (N = 12). There were 48 sham operated controls. Approximately 24 h after the operation chicks were exposed to the training stimulus. Their approach to this stimulus and to a second, novel stimulus were then measured and a preference score calculated. All five groups of chicks preferred the training stimulus and the magnitude of the preference was similar in all groups. To determine whether the IMHV region which had been intact during training was essential for retention, all chicks were anaesthetised for a second time, congruent to 20 h after the end of training. The remaining IMHV region was then destroyed. Approximately 28 h later the chicks' preferences were again measured. The sham operated and HA lesioned chicks continued strongly to prefer the training stimulus, but the birds lesioned in IMHV showed no such retention, the preference score of the IMHV chicks being significantly lower than that of the sham operated and HA lesioned chicks. The order in which the right and left sides were destroyed did not significantly influence the preference score; this result was true both for IMHV and for HA chicks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

Sexual behavior elicited in cage-mates of olfactory tubercle stimulated rats.

Fourteen male albino rats kept in pairs were implanted with bipolar electrodes in the olfactory tubercle. Electrical stimulation elicited a behavioral change in the cage-mates of the stimulated rats. This change consisted of increased exploratory activity in six animals. In three of these six rats, sexual behavior with mounting and pelvic thrusting was observed. The changes are described and discussed with special attention to sexual behavior.

Animals↗

PubMed1982