Effects on oestrous cyclicity and ovulation of unilateral section of the vagus nerve performed on different days of the oestrous cycle in the rat

1989 ◽  
Vol 123 (3) ◽  
pp. 441-444 ◽  
Author(s):  
R. Chávez ◽  
S. Sánchez ◽  
A. Ulloa-Aguirre ◽  
R. Domínguez

ABSTRACT The effects of unilateral section of the right or left vagus nerve (SRVN, SLVN) performed on different days of the oestrous cycle of the rat were analysed. Vagal nerve section on the day of oestrus or on day 1 of dioestrus (D1) altered oestrous cyclicity in a more significant way than when it was performed on day 2 of dioestrus (D2) or pro-oestrus (6/58 maintained normal oestrous cycles compared with 32/39 that did not; P<0.01). Ovulation rate at oestrus was lower in rats with SLVN than in the sham-operated group (32/47 vs 28/32; P < 0.05). The number of ova shed by the left ovary was reduced in sham-operated rats and in animals with SRVN and SLVN, whereas the number shed by the right ovary was not modified. The day of the oestrous cycle on which the vagus nerve was cut also influenced the number of ova shed. No changes in plasma levels of FSH at oestrus were observed in animals with SRVN or SLVN. The results indicate that vagal manipulations performed at the beginning of the oestrous cycle (day of oestrus and D1) induce more changes on oestrous cyclicity and ovulation than when they are performed during the second half of the cycle (D2 and pro-oestrus). In addition, the left ovary is more sensitive to neural manipulation than is the right one. Journal of Endocrinology (1989) 123, 441-444

1987 ◽  
Vol 113 (3) ◽  
pp. 397-401 ◽  
Author(s):  
R. Chávez ◽  
M. E. Cruz ◽  
R. Domínguez

ABSTRACT The possible existence of peripheral asymmetry in the neuroendocrine mechanisms participating in the response of the ovary to gonadotrophins, and the participation of the vagus nerve, was investigated. At oestrus, the ovulation rate (number of ovulating/number of treated rats) of the left ovary in right unilaterally ovariectomized rats was lower than that in the right ovary in left unilaterally ovariectomized rats (42 vs 84%). No differences in the number of ova shed per ovulating animal nor in compensatory ovarian hypertrophy (COH) were observed. Bilateral section of the vagus nerve resulted in reduced COH only in those animals with the left ovary in situ (right unilaterally ovariectomized). Section of the left vagus nerve induced different effects depending upon which ovary was left in situ. When the left ovary was in situ an increase in ovulation rate, COH and number of ova shed was observed; however, when the right ovary was left in place the above three parameters decreased. Section of the right vagus nerve produced a decrease only in COH in both right and left unilaterally ovariectomized animals. It is concluded that in the unilaterally ovariectomized rat the right ovary seems more able to react to compensatory regulatory systems than does the left. The character of the information carried by the left and right vagus nerve is different. J. Endocr. (1987) 113, 397–401


1994 ◽  
Vol 140 (2) ◽  
pp. 197-201 ◽  
Author(s):  
R Chávez ◽  
R Domínguez

Abstract The effects were analysed of section of the superior ovarian nerve on compensatory ovulation and ovarian hypertrophy, in adult rats with the left or right ovaries extirpated during the oestrous cycle and autopsied 6 or 20 days later. Rats with hemiovariectomy or hemiovariectomy plus denervation recovered their oestrous cyclicity between 2 and 3 days after surgery. Six days after hemiovariectomy 14 out of 17 rats ovulated on the expected day of oestrus. All the animals were hemiovariectomized on the day of pro-oestrus. The mean ± s.e.m. number of ova shed was similar to the group of animals with both ovaries (7·8 ± 1·2 vs 9·5 ± 0·2 Compensatory ovarian hypertrophy was observed in the right ovary when left hemiovariectomy was performed on day 2 of dioestrus or pro-oestrus; similar results were observed in the left ovary when the right one was extirpated at oestrus or pro-oestrus. Section of the right superior ovarian nerve in left-hemiovariectomized rats caused a reduction in ovulation rate and number of ova released. Compensatory ovarian hypertrophy was modified in the opposite way by unilateral section of the superior ovarian nerve to the in situ ovary depending on the day of the cycle when hemiovariectomy was performed. Twenty days after treatment, ovulation rate, compensatory ovulation and ovarian hypertrophy were similar in both left- or right-hemiovariectomized rats. Compensatory ovarian hypertrophy increased in all animals with section of the superior ovarian nerve, except when hemiovariectomy was carried out at oestrus or the left ovary was extirpated on day 1 of dioestrus. The results suggest that modulation of compensatory ovarian hypertrophy by neural information arriving at the ovary by way of the superior ovarian nerve varies during the oestrous cycle. Journal of Endocrinology (1994) 140, 197–201


1990 ◽  
Vol 124 (1) ◽  
pp. 43-45 ◽  
Author(s):  
R. Domínguez

ABSTRACT Differences were observed in the ovulation rates of the right and left ovaries in response to unilateral lesions of the cervico-vaginal plexus (CVP) followed by pseudopregnancy or by anaesthesia of the CVP induced with panthocaine plus adrenaline (right ovary 6·7±0·4 (s.e.m.) vs left ovary 4·6 ± 0·9; P<0·05). Pseudopregnancy (days showing a dioestrous smear after copulation with a vasectomized male before an oestrous smear following a pro-oestrous one) lasted longer in rats with a lesion in the CVP than in a control pseudopregnant group (14·9 ± 0·5 vs 11·2 ± 0·5; P < 0·01). Anaesthesia of the CVP performed on each day of the oestrous cycle did not modify the ovulation rate compared with laparotomized animals. Both laparotomy and anaesthesia of the CVP performed on oestrus or day 1 of dioestrus blocked ovulation but when they were performed on day 2 of dioestrus or pro-oestrus they failed to do so (laparotomy 9/18 vs 12/14, P<0·05; anaesthesia of CVP 3/11 vs 17/17, P < 0·05). The number of ova shed by the left ovary in animals with anaesthetized CVP was lower than by the right ovary (4·5 ± 0·6 vs 6·2 ± 0·5; P<0·05). These results add further support to the idea that the CVP participates in the regulation of ovulation rate, and that the left ovary is less adaptable than the right when innervation is challenged. Journal of Endocrinology (1990) 124, 43–45


2000 ◽  
Vol 89 (1) ◽  
pp. 139-142 ◽  
Author(s):  
Robert L. Coon ◽  
Patrick J. Mueller ◽  
Philip S. Clifford

The canine cervical trachea has been used for numerous studies regarding the neural control of tracheal smooth muscle. The purpose of the present study was to determine whether there is lateral dominance by either the left or right vagal innervation of the canine cervical trachea. In anesthetized dogs, pressure in the cuff of the endotracheal tube was used as an index of smooth muscle tone in the trachea. After establishment of tracheal tone, as indicated by increased cuff pressure, either the right or left vagus nerve was sectioned followed by section of the contralateral vagus. Sectioning the right vagus first resulted in total loss of tone in the cervical trachea, whereas sectioning the left vagus first produced either a partial or no decrease in tracheal tone. After bilateral section of the vagi, cuff pressure was recorded during electrical stimulation of the rostral end of the right or left vagus. At the maximum current strength used, stimulation of the left vagus produced tracheal constriction that averaged 28.5% of the response to stimulation of the right vagus (9.0 ± 1.8 and 31.6 ± 2.5 mmHg, respectively). In conclusion, the musculature of cervical trachea in the dog appears to be predominantly controlled by vagal efferents in the right vagus nerve.


2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Alice Noris ◽  
Paolo Roncon ◽  
Simone Peraio ◽  
Anna Zicca ◽  
Matteo Lenge ◽  
...  

BACKGROUND Vagus nerve stimulation (VNS) represents a valid therapeutic option for patients with medically intractable seizures who are not candidates for epilepsy surgery. Even when complete section of the nerve occurs, stimulation applied cranially to the involved nerve segment does not preclude the efficacy of VNS. Complete vagus nerve section with neuroma causing definitive left vocal cord palsy has never been previously reported in the literature. OBSERVATIONS Eight years after VNS implant, the patient experienced worsening of seizures; the interrogation of the generator revealed high impedance requiring surgical revision. On surgical exploration, complete left vagus nerve section and a neuroma were found. Vocal cord atrophy was found at immediate postoperative laryngeal inspection as a confirmation of a longstanding lesion. Both of these events might have been caused by direct nerve injury during VNS surgery, and they presented in a delayed fashion. LESSONS VNS surgery may be complicated by direct damage to the left vagus nerve, resulting in permanent neurological deficits. A complete section of the nerve also enables an efficacious stimulation if applied cranially to the involved segment. Laryngeal examination should be routinely performed before each VNS surgery to rule out preexisting vocal cord dysfunction.


1916 ◽  
Vol 24 (5) ◽  
pp. 605-619 ◽  
Author(s):  
G. Canby Robinson

The experiments that have been reported indicate that stimulation of either the right vagus or the left vagus nerve is equally effectual in blocking impulses from the auricles to the ventricles when auricular fibrillation is present. Stimulation of the left vagus nerve is as effectual in blocking impulses from the normally beating auricles as from the auricles when in a state of fibrillation, and the type of auricular activity has apparently no influence on the effect which stimulation of the left vagus has on auriculoventricular conduction.


1989 ◽  
Vol 256 (5) ◽  
pp. H1295-H1302
Author(s):  
S. A. Lang ◽  
M. N. Levy

We determined the effects of vagus nerve stimulation on cardiac cycle length and on ventricular contraction and relaxation in 18 chickens anesthetized with pentobarbital. Right vagus stimulation at a constant frequency of 35 Hz prolonged cycle length by 190%, whereas left vagus stimulation at the same frequency increased cycle length by 136%. When one burst of stimuli was delivered to the right vagus nerve each cardiac cycle, but the timing of the stimuli was changed within the cardiac cycle, the response of the avian pacemaker cells varied substantially with the timing of the stimuli. Right and left vagus stimulation at a constant frequency of 20 Hz depressed ventricular contraction by 62 +/- 6 and 52 +/- 6%, respectively, and depressed ventricular relaxation by 56 +/- 7 and 53 +/- 7%, respectively. These results indicate that in the chicken the chronotropic effects of right vagus stimulation are greater than those of left vagus stimulation, whereas right and left vagus stimulation are approximately equipotent on ventricular contraction and relaxation.


1999 ◽  
Vol 276 (2) ◽  
pp. R455-R467 ◽  
Author(s):  
F. M. Smith

Convergence of inputs from extrinsic cardiac nerves [vagus and cardiopulmonary (CPN)] on intrinsic cardiac neurons was investigated in the pig ( Sus scrofa). A segment of the right atrial wall containing epicardial neurons along with attached stumps of the right vagus nerve and CPN was maintained in vitro; intracellular recordings were made from 57 neurons. Three types of neuron were identified by their responses to long intracellular depolarizing current pulses: phasic [discharged 1 action potential (AP); 40%]; accommodating (discharged multiple APs decrementing in frequency during pulse; 33%); and tonic (discharged multiple APs at a high frequency; 27%). Sixty-six percent of the neurons responded with excitatory postsynaptic potentials (EPSP) to vagal nerve stimulation; two-thirds of these cells fired APs when EPSP amplitude exceeded threshold level. Postsynaptic responses to vagal nerve stimulation were mediated by nicotinic ion channels; responses were eliminated by hexamethonium. CPN stimulation produced EPSPs but no APs in 17% of the neurons. All neurons responding with postsynaptic depolarizations to CPN stimulation also received vagal inputs. Combined stimulation of the vagus nerve and CPN produced APs in all but one of these neurons. Timolol eliminated postsynaptic responses from CPN stimulation, indicating that these responses involved β-adrenergic receptors and likely resulted from activation of sympathetic postganglionic terminals. These results show that some intrinsic cardiac neurons receive convergent inputs from the CPN and vagus nerve. It is suggested that such neurons represent intraganglionic sites for sympathetic-parasympathetic interactions in neural control of the heart.


1972 ◽  
Vol 42 (3) ◽  
pp. 251-263 ◽  
Author(s):  
Diana Trenchard ◽  
D. Gardner ◽  
A. Guz

1. The administration of the polysaccharide carageenin through a catheter into the lungs of cats and rabbits has produced an inflammatory lesion confined to one lobe of a lung. The lesion consisted of an alveolar and interstitial infiltration with polymorphonuclear leucocytes and, subsequently, macrophages. There was no apparent damage to alveolar walls and no pleurisy. The rest of the lung remained normal. 2. In both conscious cats and anaesthetized rabbits there was an increased frequency of breathing dependent on an intact vagus nerve on the same side as the lesion. It was independent of changes in body temperature and was not due to hypoxaemia. 3. By using a direct current to the right cervical vagus nerve in the rabbits (with the left vagus nerve sectioned), it has been possible to block conduction in myelinated fibres; the non-myelinated fibres conduct normally. Studies with this differentially blocked nerve have shown that the increased frequency of breathing is dependent on activity in the non-myelinated vagal afferent fibres.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Elizabeth Vieyra-Valdez ◽  
Julio Cesar Garcia-Tabla ◽  
Hugo Alberto Zarco-Juarez ◽  
Roberto Calderon-Ramos ◽  
Leticia Morales-Ledesma ◽  
...  

Abstract Several studies show that the suprachiasmatic nucleus (SCN) participates in the regulation of the functions of various endocrine organs through multisynaptic nerve pathways. Some of these pathways communicate the SCN with the dorsal motor nucleus of the vagus and the nucleus of the solitary tract, which are part of the origin of the vagus nerve (1). Previously we demonstrated that atropine (ATR) microinjection in the right SCN on the day of the proestrus, blocks ovulation, while the same treatment in the left SCN does it partially (2). In the present study we analyzed the possibility that the vagus nerve is one of the neural ways by which the SCN regulates the secretion of estradiol (E2) in the proestrus and subsequent ovulation. For this, cyclic rats were anesthetized with ketamine-xylazine at 09.00 of the day of the proestrus. The animals were randomly assigned to one of the following groups: rats with ATR (62.5 ng diluted in 0.3 µl of saline) microinjection in the right or left SCN, followed by ventral laparotomy or ipsilateral vagotomy to the microinjection side. The animals were sacrificed 5 h after surgery, and estradiol (E2) levels were measured. Other groups of animals with the same treatments were sacrificed 24 hours after surgery, and ovulation rate and number of ova shed were evaluated. The left vagus section did not modify the effects of ATR microinjection in the left SCN on ovulatory rate (2/5 vs. 4/7) and E2 secretion (46.6±9.0 vs. 51.3±9.0, pg/ml). In animals with ATR microinjection in the right SCN, the right vagus section increased the rate of ovulating animals (6/8 vs. 2/9, p &lt;0.0001, Fisher’s exact probability test) and E2 levels (51.8±9.4 vs. 22.4 ± 4.0, p &lt;0.05, two-way ANOVA, followed by Tukey’s multiple comparison test). Present results suggest that the right vagus nerve plays a role in the multisynaptic communication between the right SCN and the right ovary, while the left vagus does not. Reference: (1) Travagli, R. A. J. Physiol. 2007 Jul 15:582(Pt 2):471. (2) Vieyra et al., Reproductive Biology and Endocrinology. 2016 Jun 16 14(1):34, 1-11.Supported by CONACyT 236908; DGAPA-PAPIIT IN216519


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