Cardiovascular effects of centrally active cholinomimetics in conscious and anesthetized rats: The role of amygdala

Özkutlu, Uǧur; Coşkun, Turgay; Onat, Filiz; Bc, Yeğen; Oktay, Şule

doi:10.1016/0361-9230(95)00031-9

Cited by 9 publications

(4 citation statements)

References 28 publications

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“…The finding that c-fos expression was induced in the fetal AV3V and the hindbrain is the evidence that the central pathway are activated and cholinergic mechanisms are functional in the control of fetal blood pressure at 90% gestation, and indicates that the fetal AV3V region in the forebrain and In mature animals, carbachol is known as a long-lasting cholinergic agonist in the brain in affecting body fluid and cardiovascular homeostasis, including increase of arterial blood pressure, release of vasopressin, and stimulation of thirst (Barbosa et al, 1995;Iitake et al, 1986;Mahon et al, 1995;Poole, 1983). Previous studies in adults showed that the pressor response induced by central administered carbachol was marked and sustained with short latency (Poole, 1983;Ö zkutlu et al, 1994). In the present study, consistent with the results in adults, the onset of the central carbachol-induced pressor responses in fetuses was rapid.…”

Section: Discussionmentioning

confidence: 99%

The Association of Cardiovascular Responses with Brain c-fos Expression after Central Carbachol in the Near-Term Ovine Fetus

Shi

Morrissey

Yao

et al. 2005

Neuropsychopharmacol

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Central cholinergic mechanisms play important roles in the control of cardiovascular responses. However, in utero development of brain cholinergic mechanism in regulation of arterial pressure before birth is largely unknown. This study investigated cardiovascular responses to central application of carbachol in fetuses and determined functional development of the central cholinergic systems controlling fetal pressor responses in utero. Chronically prepared near-term ovine fetuses (90% gestation) received an injection of carbachol intracerebroventricularly (i.c.v.). Fetal cardiovascular responses were measured, and the brains were used for c-fos mapping studies. In response to carbachol injection i.c.v., fetal systolic, diastolic, and mean arterial pressure (MAP) immediately increased, accompanied by a bradycardia. The maximum increase of MAP was at 30 min after the i.c.v. injection of carbachol and lasted 90 min. Associated with the pressor response, the neuronal activity marked with c-fos was enhanced significantly in the fetal anterior third ventricle (AV3V) region (including the median preoptic nucleus and organum vasculosum of the lamina terminalis) in the forebrain, and in the area postrema, lateral parabrachial nucleus, nucleus tractus solitary, and rostral ventrolateral medulla in the hindbrain. These results indicate that the central cholinergic mechanism is functional in the control of fetal blood pressure at the last third of gestation, and the central AV3V region and hindbrain have been intact relatively during in utero development in sheep at 90% gestational stage.

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Section: Discussionmentioning

confidence: 99%

The Association of Cardiovascular Responses with Brain c-fos Expression after Central Carbachol in the Near-Term Ovine Fetus

Shi

Morrissey

Yao

et al. 2005

Neuropsychopharmacol

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“…Indeed, both BP and HR responses to pharmacological agents have been found to be significantly different in conscious as compared to anesthetized animals. 8,28 However, a number of previous studies regarding the role of the amygdala in cardiovascular effects have been performed under anesthesia, 9,10,12 and so further investigation of the role of the amygdala via the GABAA receptors in anesthetized rats is required.…”

Section: Discussionmentioning

confidence: 99%

Role of Medial Amygdala in Controlling Hemodynamics Via GABA<sub>A</sub> Receptor in Anesthetized Rats

Yoshida¹,

Uemura²,

Iguchi

et al. 2002

Circ J

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Experiments were conducted to determine whether the medial amygdala could control hemodynamics through the GABA receptor in anesthetized rats. Bicuculline (10-100pmol), a GABA(A) antagonist, injected into the anterior basomedial amygdala (medial amygdala) produced dose-related increases in blood pressure (BP) and heart rate (HR). Following microinjection of a 100pmol dose, plasma norepinephrine and epinephrine also rose significantly. In a group that had undergone bilateral adrenalectomy, the same dose of bicuculline into the same region of the amygdala caused similar increases in BP and HR to those produced in normal rats. Pretreatment with an intraperitoneal injection of hexamethonium prevented these responses. When bicuculline was given intravenously (100pmol) it failed to effect these cardiovascular changes. Bicuculline-induced hypertension and tachycardia were inhibited by microinjection of muscimol, a GABA agonist, into the anterior basomedial amygdala. The results thus demonstrate that the influence of bicuculline on BP and HR is through action on the anterior basomedial amygdala and direct sympathetic outflow to heart and vascular smooth muscle. There is tonic GABAergic inhibition of sympathetic outflow in the medial amygdala that plays a part in regulating hemodynamics in the limbic system.

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“…Further, ablation of the central nucleus of the amygdala significantly attenuates i.c.v. carbachol‐induced pressor responses in both anaesthetized and conscious rats (özkutlu et al , 1995). These combined observations suggest that, at the level of the amygdaloid complex, cholinergic pathways acting via M 1 ‐muscarinic receptors may play an important role in the regulation of blood pressure and in stress‐induced hypertension.…”

Section: Discussionmentioning

confidence: 99%

“…Further, the pressor response evoked by the cholinomimetic carbachol (i.c.v.) was suppressed by electrolytic lesions of the central nucleus of the amygdaloid complex (özkutlu et al , 1995). The present study was designed to investigate the type of muscarinic receptor that mediates the carbachol‐evoked pressor response when injected into the central nucleus of the amygdaloid complex and whether a similar muscarinic receptor is involved in mediating the pressor response to electrical stimulation of this nucleus.…”

Section: Introductionmentioning

confidence: 99%

Modulation of the pressor response elicited by carbachol and electrical stimulation of the amygdala by muscarinic antagonists in conscious rats

Aslan

Gören

Özkutlu

et al. 1997

British J Pharmacology

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1 The nature of the muscarinic receptor involved in mediating cardiovascular changes caused by unilateral microinjection of carbachol (5 nmol) into, and electrical stimulation (200 ± 300 mA) of, the amygdaloid complex was investigated in conscious, unrestrained female Sprague-Dawley rats. 2 Unilateral microinjection of carbachol (5 nmol; n=6) and electrical stimulation (200 ± 300 mA, 80 Hz, 30 s; n=4) caused a signi®cant rise in blood pressure of 21+4 mmHg and 25+5 mmHg, respectively. These changes were associated with no overall e ect on heart rate. The e ects of electrical stimulation were found to be repeatable. 3 Pretreatment i.c.v. with pirenzepine (5 ± 20 nmol; n=6 ± 7 for each dose), dose-dependently inhibited the rise in blood pressure induced by carbachol, whereas AF-DX 116 (100 nmol; n=6) failed to have any e ect on the carbachol-induced pressure response. Neither antagonist alone had any e ect on resting baseline variables. 4 Unilateral microinjections of atropine sulphate (1 ± 100 nmol; n=4 ± 6 for each dose), pirenzepine (0.03 ± 10 nmol; n=4 for each dose) or AF-DX 116 (10 ± 60 nmol; n=4 ± 5 for each dose), into the amygdala, dose-dependently inhibited the rise in blood pressure caused by electrical stimulation (200 ± 300 mA). The ID 50 values were 1.05, 0.23 and 39.5 nmol, respectively. Although pirenzepine seemed to be more potent than atropine, this di erence was not signi®cant. 5 It is concluded that the rise in blood pressure elicited by unilateral microinjection of carbachol into, or electrical stimulation of, the amygdaloid complex is mediated by M 1 -muscarinic receptors.

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Cardiovascular effects of centrally active cholinomimetics in conscious and anesthetized rats: The role of amygdala

Cited by 9 publications

References 28 publications

The Association of Cardiovascular Responses with Brain c-fos Expression after Central Carbachol in the Near-Term Ovine Fetus

The Association of Cardiovascular Responses with Brain c-fos Expression after Central Carbachol in the Near-Term Ovine Fetus

Role of Medial Amygdala in Controlling Hemodynamics Via GABA<sub>A</sub> Receptor in Anesthetized Rats

Modulation of the pressor response elicited by carbachol and electrical stimulation of the amygdala by muscarinic antagonists in conscious rats

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