title: The effects of temperature and synaptic blockade in vitro on neurons of the horizontal limb of the diagonal band of Broca in the rat basal forebrain.
abstract: We studied the thermosensitivity of neurons in the rat horizontal limb of the diagonal band of Broca (HDB) in vitro under normal conditions and under conditions of a low calcium/high magnesium synaptic blockade (SB). Of 52 HDB neurons tested, 34 neurons (65%) were warm-sensitive (WS), three neurons (6%) were cold-sensitive (CS), 11 neurons (21%) were temperature-insensitive (TI) and four additional neurons (8%) were both warm- and cold-sensitive (WS/CS). Of 34 neurons tested for thermosensitivity under SB, 11 were WS, 4 were CS and 19 were TI. Nearly half (48%) of the WS neurons maintained warm sensitivity under SB, 43% became TI and 9% became CS. Baseline firing rates of neurons significantly decreased during SB and then increased during recovery from SB. In addition, a distinct anatomical distribution of thermosensitive neurons was found in the HDB. The most ventral aspect of the HDB (interaural +0.9-1.3 mm) had proportionally fewer temperature sensitive neurons (65% vs. 88%) than areas more dorsal (interaural +1.3-1.7 mm), and only one of seven ventral HDB neurons (14%) remained thermosensitive during SB. In the dorsal HDB, 65% of the neurons maintained thermosensitivity during SB. These results demonstrate that the HDB contains inherently thermosensitive neurons, and that a difference in thermal characteristics exists between the ventral and dorsal HDB neurons.
authors.affiliation: Program in Neuroscience, University of California, Los Angeles, USA.
authors.forename: T
authors.initials: T
authors.lastname: Hays
authors.forename: S
authors.initials: S
authors.lastname: Morairty
authors.forename: R
authors.initials: R
authors.lastname: Szymusiak
authors.forename: D
authors.initials: D
authors.lastname: McGinty
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology*; D004594:Electrophysiology; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology*; D009924:Organ Culture Techniques; D016548:Prosencephalon / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects*