This study examined the effects of intracisternally injected serotonin on cerebral blood flow and systemic pressure in cats during winter and summer months. The researchers found that serotonin produced decreases in cerebral blood flow and systemic pressure lasting 60 to 180 minutes after injection. The decreases in blood flow were significantly greater in winter than summer, but decreases in systemic pressure were not different between seasons. Cats exposed to 3 days of darkness before serotonin injection experienced greater decreases in blood flow compared to light-exposed cats, while systemic pressure changes were similar. The findings suggest the photoperiod may affect the sensitivity of cerebral vessels to serotonin in cats.
1. Summary
Chronobiology International
1993, Vol. 10, No. 6, Pages 442-448
Effects of Intracisternally Injected Serotonin on Cerebral Blood Flow in
Cats During Winter and Summer, and After Dark Exposure
1† 1 1 1 2
Phillip E. Vinall , John J. Michele , David A. Gordon , Christopher Deitch and Frederick A. Simeone
1
Department of Nenrosurgery, Pennsylvania Hospital, Philadelphia, Pennsylvania
2
Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
†
Correspondence: Phillip E. Vinall, Neuroscience Research Institute, Pennsylvania Hospital, 800 Spruce Street,
Philadelphia, PA, 19107, USA
This investigation reports on two experiments: (a) The examination of the effects of intracisternally
injected serotonin on cerebral blood flow and systemic pressure in cats during winter (1/10–3/7) and
summer (7/6–9/3) at a latitude of 39' 40, and (b) the effects of similarly injected serotonin on the same
parameters in 11 cats after exposure to 3 days of continuous darkness during the summer months.
Serotonin (5 mg) injected intracisternally produced significant decreases in cerebral blood flow and
systemic pressure that lasted from 60 to 180 min after injection. Blood flow decreases, expressed as
percentage change from baseline, seen during winter (n = 24) periods were significantly greater [analysis
of variance (ANOVA), p < 0.02] from decreases seen during summer (n = 25) periods. Following
serotonin injection, systemic pressure decreases between the winter and summer cats were not
significantly different. Eleven summer cats were subjected to 3 days of continuous darkness before being
injected with serotonin. Blood flow decreases in the dark-exposed cats were significantly (p < 0.05)
greater than those seen in normal light-exposed cats, whereas systemic pressure changes were not
different. These studies suggest that the seasonal photoperiod may affect the sensitivity of cerebral
vessels to intracisternally injected serotonin in cats.
![Summary
Chronobiology International
1993, Vol. 10, No. 6, Pages 442-448
Effects of Intracisternally Injected Serotonin on Cerebral Blood Flow in
Cats During Winter and Summer, and After Dark Exposure
1† 1 1 1 2
Phillip E. Vinall , John J. Michele , David A. Gordon , Christopher Deitch and Frederick A. Simeone
1
Department of Nenrosurgery, Pennsylvania Hospital, Philadelphia, Pennsylvania
2
Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
†
Correspondence: Phillip E. Vinall, Neuroscience Research Institute, Pennsylvania Hospital, 800 Spruce Street,
Philadelphia, PA, 19107, USA
This investigation reports on two experiments: (a) The examination of the effects of intracisternally
injected serotonin on cerebral blood flow and systemic pressure in cats during winter (1/10–3/7) and
summer (7/6–9/3) at a latitude of 39' 40, and (b) the effects of similarly injected serotonin on the same
parameters in 11 cats after exposure to 3 days of continuous darkness during the summer months.
Serotonin (5 mg) injected intracisternally produced significant decreases in cerebral blood flow and
systemic pressure that lasted from 60 to 180 min after injection. Blood flow decreases, expressed as
percentage change from baseline, seen during winter (n = 24) periods were significantly greater [analysis
of variance (ANOVA), p < 0.02] from decreases seen during summer (n = 25) periods. Following
serotonin injection, systemic pressure decreases between the winter and summer cats were not
significantly different. Eleven summer cats were subjected to 3 days of continuous darkness before being
injected with serotonin. Blood flow decreases in the dark-exposed cats were significantly (p < 0.05)
greater than those seen in normal light-exposed cats, whereas systemic pressure changes were not
different. These studies suggest that the seasonal photoperiod may affect the sensitivity of cerebral
vessels to intracisternally injected serotonin in cats.](https://image.slidesharecdn.com/serotoninandbloodflow-100604161615-phpapp02/85/Serotonin-and-blood-flow-1-320.jpg)
