Electrophysiology of Kisspeptin Neurons - Kisspeptin Signaling in Reproductive Biology - page 339

Chapter 16
Electrophysiology of Kisspeptin Neurons
Meenakshi Alreja
Abstract Kisspeptin is an important regulator of reproduction. Electrophysiological
studies show that kisspeptin neurons of the arcuate nucleus that co-localize neuro-
kinin B and dynorphin (aka KNDy neurons) fi re action potentials in a tonic, irregular,
or burst fi ring manner. Gonadectomy dramatically alters the membrane properties
of KNDY neurons from male mice and induces somatic hypertrophy. NMDA,
leptin, and neurokinin B are potent activators of KNDY neuron electrical activity
and GABA inhibits KNDY neurons. The fi ring pattern of kisspeptin neurons located
in the RP3V fl uctuates with the estrus cycle and is strongly modulated by glutamate
and GABA. Thus, kisspeptin neurons are capable of burst fi ring, and their activity
is modulated by sex steroids and other regulatory factors.
Introduction
Electrophysiological studies provide an excellent tool for dissecting out cellular and
molecular mechanisms that control cell fi ring, especially when in vivo and in vitro
approaches are combined with neuropharmacological analysis. With respect to the
reproductive system, in vivo approaches in large animals have the distinct advan-
tage of allowing simultaneous monitoring of neuronal fi ring patterns and gonado-
tropin release mechanisms. In vitro electrophysiology allows study of intrinsic
membrane properties, as well as second messenger and ionic mechanisms.
Studies on the electrophysiological properties of identifi ed kisspeptin neurons
lagged until recently, due to a lack of appropriate tools for unequivocal identifi cation
M. Alreja , Ph.D. ( * )
Yale University School of Medicine, CMHC W-215, 34 Park Street,
New Haven , CT 06508 , USA
e-mail: [e-mail]