GABA receptors in the region of the dorsomedial hypothalamus of rats regulate anxiety in the elevated plus-maze test. II. Physiological measures

Anantha Shekhar, L. S. Sims, R. R. Bowsher

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

In the previous report, we had shown that blockade and enhancement of GABAA receptors in the DMH of rats increased or decreased the level of anxiety, respectively, as measured by the elevated plus-maze test. The present study was conducted to assess the effects of enhancing GABAA neurotransmission in the DMH of rats on the physiological concomitants of anxiety such as increased in heart rate (HR), blood pressure (BP) and plasma norepinephrine (NE) levels while the animals were placed on the elevated plus-maze. Male Sprague-Dawley rats were equipped with arterial and venous catheters and stereotaxically implanted with microinjection cannulae in the cardiostimulatory region of the DMH where injection of bicuculline methiodide (BMI) elicited increases in heart rate under anesthesia. After recovery, rats were injected with either saline or the GABAA agonist muscimol and their HR, BP and plasma NE responses were measured when confined in the open or the closed arm of the elevated plus-maze. Injection of muscimol into the DMH reduced the increases seen in HR, BP and plasma NE when the rats were confined to either the closed or the open arms in addition to decreasing 'anxiety' in the plus-maze. Injection of muscimol into the areas of the hypothalamus surrounding the DMH did not significantly affect the changes in HR, BP and plasma NE in the plus-maze. Blocking the changes in HR and BP elicited by microinjecting GABAergic drugs into the DMH of rats, with systemic injections of a combination of atropine and the beta-blocker atenolol, did not block the behavioral effects of the GABAergic drugs in the plus-maze test.

Original languageEnglish
Pages (from-to)17-24
Number of pages8
JournalBrain Research
Volume627
Issue number1
DOIs
StatePublished - Nov 5 1993

Fingerprint

Dimenhydrinate
GABA Receptors
Hypothalamus
Anxiety
Heart Rate
Muscimol
Blood Pressure
Norepinephrine
Injections
GABA-A Receptor Agonists
Atenolol
Microinjections
GABA-A Receptors
Atropine
Synaptic Transmission
Pharmaceutical Preparations
Sprague Dawley Rats
Catheters
Anesthesia

Keywords

  • Anxiety
  • Atenolol
  • Benzodiazepine
  • Bicuculline methiodide
  • Blood pressure
  • Gamma-aminobutyric acid
  • Heart rate
  • Hypothalamus
  • Muscimol

ASJC Scopus subject areas

  • Developmental Biology
  • Molecular Biology
  • Clinical Neurology
  • Neuroscience(all)

Cite this

GABA receptors in the region of the dorsomedial hypothalamus of rats regulate anxiety in the elevated plus-maze test. II. Physiological measures. / Shekhar, Anantha; Sims, L. S.; Bowsher, R. R.

In: Brain Research, Vol. 627, No. 1, 05.11.1993, p. 17-24.

Research output: Contribution to journalArticle

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