title: Effects of prostaglandin E2 on the electrical properties of thermally classified neurons in the ventromedial preoptic area of the rat hypothalamus.
abstract: BACKGROUND
  Physiological and morphological evidence suggests that activation of the ventromedial preoptic area of the hypothalamus (VMPO) is an essential component of an intravenous LPS-dependent fever. In response to the endogenous pyrogen prostaglandin E2 (PGE2), the majority of temperature insensitive neurons in the VMPO show an increase in firing rate, while warm sensitive neurons are inhibited. We have hypothesized that these PGE2 dependent effects on firing rate are due to changes in the inherent electrical properties of VMPO neurons, which are regulated by the activity of specific ionic currents.
  
  
  RESULTS
  To characterize the electrical properties of VMPO neurons, whole-cell recordings were made in tissue slices from male Sprague-Dawley rats. Our results indicate that PGE2 dependent firing rate responses were not the result of changes in resting membrane potential, action potential amplitude and duration, or local synaptic input. However, PGE2 reduced the input resistance of all VMPO neurons, while increasing the excitability of temperature insensitive neurons and decreasing the excitability of warm sensitive neurons. In addition, the majority of temperature insensitive neurons responded to PGE2 with an increase in the rate of rise of the depolarizing prepotential that precedes each action potential. This response to PGE2 was reversed for warm sensitive neurons, in which the prepotential rate of rise decreased.
  
  
  CONCLUSIONS
  We would therefore suggest that PGE2 is having an effect on the ionic currents that regulate firing rate by controlling how fast membrane potential rises to threshold during the prepotential phase of the action potential.
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, Virginia 23187, USA. hjrane@hotmail.com <hjrane@hotmail.com>
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Ranels
authors.forename: John D
authors.initials: JD
authors.lastname: Griffin
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D015232:Dinoprostone / Q000494:pharmacology*; D006358:Hot Temperature; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D011301:Preoptic Area / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013696:Temperature; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects* / Q000502:physiology
chemical_list: D015232:Dinoprostone
references.citation: J Comp Neurol. 2000 Dec 4;428(1):5-20
references.pmid: 11058221
references.citation: J Comp Neurol. 2000 Dec 4;428(1):20-32
references.pmid: 11058222
references.citation: J Neurophysiol. 2000 Dec;84(6):2896-903
references.pmid: 11110819
references.citation: Clin Infect Dis. 2000 Oct;31 Suppl 5:S168-77
references.pmid: 11113020
references.citation: Am J Physiol Regul Integr Comp Physiol. 2001 Sep;281(3):R706-15
references.pmid: 11506983
references.citation: J Physiol. 2001 Dec 1;537(Pt 2):521-35
references.pmid: 11731583
references.citation: Brain Res. 2003 Feb 21;964(1):42-50
references.pmid: 12573511
references.citation: J Physiol. 2003 May 15;549(Pt 1):21-36
references.pmid: 12651919
references.citation: Front Biosci. 2003 Sep 1;8:s1398-408
references.pmid: 12957844
references.citation: J Physiol. 1971 Dec;219(3):739-45
references.pmid: 5157600
references.citation: J Physiol. 1973 Jul;232(1):163-79
references.pmid: 4733481
references.citation: J Physiol. 1974 Aug;240(3):639-60
references.pmid: 4416218
references.citation: Am J Physiol. 1982 Jan;242(1):R77-84
references.pmid: 7058933
references.citation: Brain Res Bull. 1983 Jun;10(6):853-7
references.pmid: 6311362
references.citation: Brain Res Bull. 1983 Nov;11(5):519-26
references.pmid: 6365250
references.citation: Brain Res Bull. 1988 Jan;20(1):75-82
references.pmid: 3124931
references.citation: Brain Res. 1988 Jun 28;454(1-2):361-7
references.pmid: 2841998
references.citation: J Physiol. 1988 Nov;405:713-25
references.pmid: 3255803
references.citation: J Physiol. 1991 Jan;432:99-110
references.pmid: 1886074
references.citation: J Physiol. 1992 Aug;454:197-212
references.pmid: 1474492
references.citation: N Engl J Med. 1994 Jun 30;330(26):1880-6
references.pmid: 7832832
references.citation: Brain Res. 1994 Nov 14;663(2):287-92
references.pmid: 7874513
references.citation: J Physiol. 1995 Oct 15;488 ( Pt 2):407-18
references.pmid: 8568679
references.citation: J Physiol. 1996 Apr 1;492 ( Pt 1):231-42
references.pmid: 8730598
references.citation: J Neurosci. 1996 Oct 1;16(19):6246-54
references.pmid: 8815905
references.citation: J Comp Neurol. 1996 Jul 15;371(1):85-103
references.pmid: 8835720
references.citation: Trends Neurosci. 1997 Dec;20(12):565-70
references.pmid: 9416669
references.citation: Am J Physiol. 1998 Mar;274(3 Pt 2):R783-9
references.pmid: 9530246
references.citation: J Neurosci. 1998 Aug 15;18(16):6081-92
references.pmid: 9698303
references.citation: J Neurophysiol. 1998 Nov;80(5):2710-7
references.pmid: 9819275
references.citation: Ann N Y Acad Sci. 1998 Sep 29;856:108-15
references.pmid: 9917871
references.citation: J Physiol. 1999 Apr 1;516 ( Pt 1):163-78
references.pmid: 10066931
references.citation: Neurochem Int. 1999 Nov;35(5):345-55
references.pmid: 10517695